(MONEY Magazine) – Ever wonder if you're being paid what you're worth? Your employer is unlikely to share meaningful salary data with you--and if you're like most of us, asking your colleagues what they make is simply out of the question. But now you can find out.

Dozens of Internet sites, from online job-hunting bazaars such as Monster.com and CareerMosaic.com to niche sites like one devoted to engineering careers, EETimes.com, offer some salary information. But the best online sources are sites that focus exclusively on compensation for hundreds of professions, from senior accountants to warehouse managers. These sites help you figure out what you're really worth on the open market--and they take much of the guesswork out of salary negotiations, whether you're dealing with your current boss or looking for a new job. "Having that knowledge means better bargaining, since the employee is no longer in the dark," says Bob Hughes, president of the salary site CompGeo Online. To find out which compensation websites offer more help than hype, six MONEY reporters reviewed dozens of career sites, finally zeroing in on the nine specialized compensation sites that provide the most comprehensive salary and benefits data in an easy-to-navigate form. The sites we like best allow you to drill down into the numbers by specific job titles and by state, city, even zip code; most also give ranges for base pay and perks for a variety of titles on a career ladder, which can help you estimate future earnings potential. (For a more detailed explanation of our ranking of nine leading sites and their Web addresses, see "Scorecard" on page 113.) Next, we asked career specialists how to use salary sites to get the best information as efficiently as possible. These experts also furnished negotiating techniques so you can use salary intelligence to your advantage. (See "The Art of Asking for More" on page 117.)

Finally, we talked to scores of people who've used these sites to bargain for fatter paychecks. Their experiences provide real-world testimony to the possibilities of negotiating pay and perks when you, and not just your employer, know what the market will bear.

Webmaster Jeffrey Tindillier, 31, for example, boosted his salary by $20,000 and snagged a $5,000 signing bonus plus stock options after consulting one of our top sites. The way Tindillier tells it, he knew his eight years of Internet experience was especially valuable in the tight Dallas job market--but he had no idea just how valuable. "I was curious to see what people in my profession were making," he says. After logging on to www.salary.com, Tindillier discovered that Webmasters in his area were earning a lot more than he was.

"People don't understand how much money they're worth in this economy," says Tindillier. Without the ammunition from his online search, he adds, he never would have had the confidence to ask for the signing bonus and lucrative stock options he received from his new employer.

THE LAY OF THE LAND

The sheer volume of information on the Internet can be overwhelming, so it helps to understand how the compensation sites work and how they differ from one another before you begin clicking.

--Free vs. pay sites. Some salary sites charge users for compensation reports; others give away data for free and get revenue from advertising and fees from other sites. Plenty of the free information at sites like Salary.com, our No. 1 pick, is topnotch, especially for entry-level staff and middle managers. Executives, though, may find it worthwhile to shell out as much as $299, as we did, or even more at a site like CompGeo Online for the kind of sophisticated report that human-resources departments use to set pay scales.

--Range of jobs. Salary sites differ significantly in scope. The most useful ones generate reports for various ranks within each job category--from junior staffer to deputy manager to senior vice president--across a wide range of industries. Except for niche sites, those that cover a limited number of job titles usually lack detailed compensation information.

--Search engines. Better sites, such as America's Career InfoNet, give you more than one method to find the salary particulars you need. When you know what you're looking for, keyword search tools let you target relevant data quickly. If you're not certain which job title applies, pulldown menus of predefined job fields lead you to relevant facts.

--Sources. Salary sites obtain data from a variety of sources, including government labor statistics, company surveys and polls of professionals in the field. Although government stats tend not to be as current as company figures, they're usually more inclusive and far reaching.

The best sites let users know where their salary numbers come from--a valuable service that sheds light on how relevant and timely the information is. We preferred sites that rely on objective and extensive data from a variety of professional sources catering to specific industries to sites that rely on voluntary submissions for data, since this information may not be representative.

CLICK THROUGH THE CLUTTER

Whatever your job, wherever you work, following these guidelines will help you get the most from your research.

--Start big. General salary sites such as those run by Salary.com and the Economic Research Institute are the best places to begin. These portals give instant access to surveys for hundreds of job titles and professions in many locations. Many of these inclusive sites also offer career advice and industry and job market overviews to help you put the salary statistics in context.

--Use at least one niche site. As you check out the general sites we discuss below, look for resource links to niche sites that focus on your particular career and industry. These provide even more precise pay figures and in-depth counseling. For example, one niche site, Law.com (www.lawjobs.com), posts several salary surveys, including one from the National Law Journal, which covers compensation for law school professors, public interest lawyers, law clerks and public defenders, to name only a few. That kind of detail is likely to be more useful than a salary report for "attorneys" or "lawyers."

--Read job descriptions, not just job titles. Titles can vary from website to website and company to company. You should search under professional categories and read job descriptions to identify the ones that apply. After all, your experience as a sales manager may be very different from the sales manager jobs included in a survey. (Tindillier says he couldn't find any listings for Webmasters on Salary.com, so he used earnings reports for Web security administrators, whose job description matched his experience securing Web servers with firewalls and protecting networks from hackers.)

--Consult more than one site. Cross-check three to five sites to be sure the numbers are in the same ball park. At least one of the sites should be specific to your profession.

--Be honest about your skills. All those dollar signs are worth little if you don't have the skills or experience to do the job that merits them. Look for surveys that are based on skill levels and set realistic goals for yourself.

After about a year as an interactive producer in New York City, Bo Rosser, 29, knew she wouldn't get a top salary for the category. So when she was offered her current job at The FeedRoom website, she negotiated a salary that reflected her yearlong experience creating interactive stories and video for the Web. Rosser was able to figure out a fair salary by using the Careerjournal site, where pay statistics showed that the top 25% of her colleagues were earning $59,000, but the average compensation was closer to $51,000.

--Know your industry. In the end, compensation surveys are averages. Salaries for, say, an accountant or an office manager can vary widely from one industry to another, says Michelle Halverson, 38. She should know. She's worked as a human-resources expert in social services, technology and now the food business, as vice president of human resources for Olympic Foods, a juice manufacturer in Spokane.

To set a realistic salary goal before accepting her current job, Halverson ordered a salary survey for human-resources jobs in manufacturing firms in Spokane from Salary Source, a site that is more appropriate for human-resources professionals. "It was wonderful to put my hands on information that was current," she says. "My present employer had done his own research, so our numbers were pretty compatible. We were able to do some quick negotiating and hammered out an agreement."

THE BEST ON THE WEB

After discarding sites with unreliable information, difficult navigation and overly complicated pricing, we settled on the nine compensation sites that offer the most useful and accessible data for the widest range of people. The sites have distinct strengths. Some are better for beginners, others for people in certain fields--but all are valuable research tools. Here are our eight favorite free sites, listed in descending order, followed by one outstanding site that charges a range of fees.

--SALARY.COM (www.salary.com). Our No. 1 site offers the best of all worlds. With 1,100 job titles in its database, Salary.com is the powerhouse in the category, yet its streamlined design makes it a snap to use. Within two mouse clicks from the home page, the Salary Wizard search engine offers reports that include base pay and salary ranges for narrowly defined job titles in specific regions. Click again, and you get total compensation (including extras such as bonuses). Handy links let you see what you would make in various parts of the country or if you changed careers. Bottom line: This is the place to start your search.

--AMERICA'S CAREER INFONET (www.acinet.org). Funded by the U.S. Department of Labor, the site covers more than 460 occupations, from oilfield roustabouts to motion-picture projectionists. If you're in an unusual industry or thinking about a career switch, it's a great resource. Salary data is just three clicks off the home page. Type in a job title for a keyword search or select a predefined "job family" from the scroll-down menu one click from the home page. We like the links to other information, including skills needed for each job, job market outlook and job postings listed by state and profession.

--U.S. DEPARTMENT OF LABOR (www.bls.gov/ocohome.htm). This site is not perfect. We wish there were more charts to make the statistics easier to read. Limited salary reports cover just 254 jobs and offer only national median earnings. That said, the site's thorough job descriptions give rich detail about the nature of the jobs that are included and the education and skills needed for advancement, making it a good choice for entry-level and middle managers who are mapping out their next career moves.

--ECONOMIC RESEARCH INSTITUTE (www.erieri.com/doltrends). The site's search engine allows you to search by zip code or by state and city. Positions are listed alphabetically, not by industry, making it time consuming to obtain data for various jobs in a particular field. If you're willing to schlep through the entire alphabet, though, you'll find precise job titles that aren't often listed on other sites. For example, rather than a generalized listing for "doctors," we found reports for chiropractors, periodontists, pediatricians, dental ceramists (and their assistants) and on and on. Salary data are listed as averages, not as the more helpful ranges.

--FUTURESTEP (www.futurestep.com). This is the site for ambitious mid- to senior-level corporate executives. Futurestep, which is a subsidiary of the executive search giant Korn/Ferry International, presents tailored earnings "profiles" for each user who registers at the site. Registration, which involves the types of work-style and personality tests administered by recruiters or career counselors, took us about an hour. Questions covered career and salary history, career objectives, personality traits and work priorities. Twenty-four hours later, you log back in to your secure account to retrieve a personal earnings estimate of what you're worth. You'll also get feedback, with a detailed analysis (you're "analytical," perhaps, or "collaborative") and a list of the careers for which you are best suited. We thought the report was trenchant and helpful for those who don't mind revealing information about themselves and being put in a database to be considered for openings being filled by Futurestep.

--JOBSTAR (www.jobstar.org). This federally funded website is tailored to the California market, but its Salary Info link is a great tool no matter where you are. Placed on the home page, the link leads to roughly 300 industry-specific salary reports produced by professional organizations, publications or other niche websites. Think of the JobStar site as an online library to find professional groups nationwide, from geologists to graphic artists. But be warned: The quality of the reports varies greatly. Smart users will contact sources directly for more details.

--WAGEWEB (www.wageweb.com). If you're just looking for a quick hit of stats, Wageweb is very simple to use--but that's because there's so little free information there. The free reports for roughly 170 job titles are organized under eight broad categories (administrative, engineering, sales/marketing and so on) listed on the home page. For a $169 to $219 annual fee, members can obtain more detailed reports. However, since the data comes from Wageweb subscribers and others, pay figures for any one job may come from fewer than 100 respondents.

--CAREERJOURNAL (www.careerjournal.com). If finding sophisticated career advice matters more than salary data, this site, run by Dow Jones & Co., publisher of the Wall Street Journal, is for you. The site's best features are articles that give incisive tips on, say, negotiating for a raise. Although there are some salary reports from reputable sources, such as the Treasury Management Association Journal, we found other data to be inconsistent and sometimes just plain useless. Many reports, for example, didn't break down salaries by region. In fact, the regional profiles link to general news articles about jobs in various areas, but not to specific compensation data.

--COMPGEO ONLINE (www.compgeo.net). This site is not free. Plus it's so ugly, it's tempting to log off immediately. (Was it the cluttered graphics or the prison-green, brown and purple color scheme that drove us to distraction?) Nevertheless, middle- to senior-level executives willing to ignore the poor design and spend some money can obtain extremely useful data.

The $39 reports don't offer much that can't be found on a free site. But when we spent $299 for a legal salaries report, we received a nearly 50-page trove of information that's normally used by human-resources departments and recruiters, with ranges of compensation for precisely defined jobs in various cities and towns nationwide. It also documented average pay increases and compared salaries by region and in public and private sectors.

You probably should download a sample to see what kind of information you'll receive for your money. That's because the explanation of what's contained in the reports at different price points can be quite confusing. This site gives you a chance to peek at the kind of information employers get all the time--but if slogging through mountains of detailed data gets you down, you may not appreciate the opportunity.