(MONEY Magazine) – Years ago I owned an album by a short-lived '60s pop band called The Left Banke that featured the gorgeous song "Walk Away Renee." Sometime during the Reagan or Bush Administrations, the record disappeared. But while browsing the Internet recently, I was thrilled to find a Left Banke greatest-hits album at an online music store, complete with a song sample of "Walk Away Renee." After listening to a few bars, I fell in love with the tune again.

Welcome to the Internet music revolution, part two. For the past couple of years, online music shopping has been about bargain prices and vast catalogues. Now the best sites have evolved into the digital equivalents of knowledgeable record store clerks, with helpful reviews, discographies and other resources that let you trace an artist's career or explore an entire musical genre, from bebop to baroque. Better yet, thanks to free downloadable software, you can listen to any one of thousands of music samples right at your computer, making it easy to catch up with new releases, find old favorites and discover little-known gems.

This revolution is a work in progress, however. Most music sites offer only a handful of samples per album, usually muffled, 30-second mono clips. Yet the sound quality is improving quickly, and downloading the free audio software right from the sites is relatively easy to do. RealPlayer is the most common, but higher-quality formats, such as Liquid Audio, are also available. The controversial MP3 music downloading system is just beginning to make its way into Web CD stores (see the box on page 148). Whatever the system, stereo speakers and a fast Internet connection will help you take full advantage of the sound and avoid lengthy waits.

After listening in at more than a dozen CD sites, I found myself returning most often to the three standouts described below. Bear in mind, these online outlets are great for browsing but don't necessarily offer the best prices. Bargain hunters may want to start their search at a price-comparison site such as www.mysimon.com. Or go right to the online retailers www.cduniverse .com and www.cdconnection.com, where I often found the lowest prices--which are usually just $1 below the highest. Now for the sites:

WWW.TUNES.COM Backed by music magazines Rolling Stone, Down Beat and The Source, Tunes.com is a dilettante's paradise. Boasting more than one million music samples (via RealPlayer), the site lets you explore nearly 200 different musical genres, from '80s postpunk to New Orleans jazz. You'll also find detailed reviews and discographies provided by the database website www.allmusic.com. Additional info is a click away on the magazine sites--Rolling Stone, for example, offers more than a thousand (kind of grainy) music videos, which can be viewed via RealPlayer.

Despite its high-powered connections, Tunes.com retains a home-grown feel. Music fans can write their own reviews and post to message boards. I especially liked the on-target recommendations--from both the site and fans--that pop up on each page. Browsing in the South African music department, for example, I was steered toward a little-known reggae singer named Lucky Dube. After listening to Dube's soulful, impassioned voice, I added his album Taxman to my wish list.

The site has some weaknesses. You won't find the newest releases, and the classical section is a bit skimpy. But whether you want to sample Radiohead's oeuvre or explore swing music's progenitors, this is a great place to start.

WWW.CDNOW.COM The recent merger of rivals CDnow and Music Boulevard looks like a plus for consumers. The newly combined site builds on CDnow's vast rock, jazz and classical lineup. But the choices, which were grouped into seven broad headings at the old CDnow, are now organized into Music Boulevard's more browse-able 16 categories.

Wisely, CDnow has also hung on to Music Boulevard's higher-quality sound samples in MPEG format, though RealPlayer samples still predominated when I visited the site in May. Much of Music Boulevard's superior editorial content is still here as well, including reviews and album information drawn from sources such as www.muze.com and the news service Allstar. You'll also find Music Boulevard's superb classical music search engine, which enables you to hunt by instrument, ensemble and even catalogue number.

WWW.AMAZON.COM As you would expect, Amazon's music department gives you a clean layout, easy navigation and helpful, if usually upbeat, reviews. This site has been quick to offer free exclusive singles downloads from upcoming albums in MP3 and Liquid Audio format, which allow you to save the entire song on a CD or your hard drive. Recently, for example, you could grab the Sarah McLachlan singles "I Will Remember You" and "Building a Mystery." As on the other music sites, you can listen to intriguing recommendations. I sampled the cult classic "Oar" by Skip Spence, the former Moby Grape guitarist, and was transported by Mahler's Symphony No. 1 as performed by the Bavarian Radio Symphony--for 30 seconds, anyway. Now where did I put my credit card?

E-mail your online shopping questions to virtual_consumer@moneymail.com.