(FORTUNE Magazine) – Dear Annie: I'm thinking about pursuing an MBA online, and I'm wondering, are there any reputable programs that will accept me without an undergraduate degree? I have many years' experience in both the public and private sectors and have been part of the top management team at two retail companies. But despite a wealth of practical knowledge, I never went back to finish college. Can I get an MBA anyway? --Jake

Dear Jake: You've actually raised several different questions here, and they're all good ones. First, "life experience"--or its pinstriped doppelganger, business experience--rarely counts for many, if any, credits toward a degree from a legitimate university. Almost all the long-distance MBA programs that will take you without a bachelor's degree are diploma mills (in the U.S., anyway; Europe is a somewhat different story). That is, they are unaccredited schools that promise you a "degree" in 30 days or so without your having to crack a book--as long as you have a valid credit card. How can you tell the diploma mills from the real deal? We'll get to that in a minute, but first, two other points: Even if a top-notch online MBA program would admit you without an undergraduate sheepskin, you'd probably regret it pretty quickly. And depending on what you're doing and where you want to go, it's possible that you don't need an MBA at all.

A bit of background: Online education, which is also known as distance learning, is growing like crazy. Enrollment has nearly doubled since 1995, with more than half (56%) of the nation's two-and four-year degree-granting institutions now offering at least some courses, according to the U.S. Education Department's National Center for Education Statistics (www.nces.ed.gov). About three million Americans are currently signed up. MBA programs in particular have mushroomed. There are now 103 accredited B-schools offering master's degrees online. When Vicky Phillips, CEO of a distance-learning research and consulting firm called Get Educated (www.geteducated.com), started tracking all this in 1989, there were just three schools doing so. Says Phillips: "MBAs are by far the most popular online degree programs, largely because an MBA is so prestigious. It has a mystique."

Unfortunately, she says, most people have a hazy understanding of what getting an MBA actually requires. You say you have lots of real-world experience, but you've been out of school for a while--or never had much formal schooling to start with, particularly in college-level math? Look out. "A master's in business administration is a highly quantitative degree," says Phillips. "If you don't have the theoretical academic background in calculus, statistics, and economics, it's very hard to pass graduate-level courses. Twenty years of hands-on experience, even as a CEO, won't help you pass a calculus-based course." Hey, nothing on earth would help me pass a calculus-based course--especially not more calculus courses--but let's not talk about that.

The fame of Harvard's highly verbal (one might almost say garrulous) case-study method has inspired plenty of imitators, and there's nothing wrong with that. But the emphasis on insightful talk also seems to have obscured, in many people's minds, what a typical MBA curriculum is about: numbers, numbers, and more numbers. Stuff like input-output modeling systems! Oh, you can't set up a basic computer program to do that? Or you don't even know what that is? You can slink away quietly, but your tuition is nonrefundable. Unless you're into finance or accounting in a pretty sophisticated way (that is, unless you're what Wall Streeters call a quant), a master's degree in management would probably be a better bet--both more attainable and more useful. That's true whether you pursue it online or off.

Now, a bit about how to steer clear of diploma mills. (They tend to be vigorous spammers, incidentally. When was the last time Stanford or Duke spammed you? Never? Exactly.) Anybody who's thinking of enrolling in an online degree program might want to take a good look at www.geteducated.com/articles/degreemills.htm, an FAQ that lists the top ten signs of a self-styled "university" that's really just a fly-by-night outfit. For help choosing among accredited online programs that you might actually want to consider, go to the website's home page and get a free download of a detailed guide, Best Distance Learning Graduate Schools--Business & Management 2003.

If you're still intent on going after an online MBA, a couple of tips from Phillips. First, a degree can cost anywhere from $5,000 to $100,000 "for a very similar curriculum of 12 to 15 courses," she says. "The main cost distinction you'll see is between public and private universities. Private ones tend to cost more, not because they are necessarily that much better, but because they are not subsidized by taxes." Which programs are likely to do most for your career? "Employers tend to favor 'backyard brands,' meaning names they know," Phillips says. She adds that the diploma you eventually earn online won't say anywhere on it that you got it without ever setting foot in a bricks-and-mortar classroom, so for maximum effect, try to choose a program whose physical location wouldn't demand a mind-and wallet-boggling commute. "If, for example, you've always lived in Massachusetts and you work in Massachusetts, an online degree from UMass is probably a very good idea," she says. "The University of Southern California is an excellent school, but it might look a little funny on your resume."

Send questions to askannie@fortunemail.com. Annie offers advice weekly at www.askannie.com.