NEW YORK (Money Magazine) - On a rainy afternoon in April, I dropped into the record store -- excuse me, CD store -- across the street from my office in Manhattan.

I didn't buy anything. I just wanted to remind myself one more time of what a CD store looks like, before they go the way of soda fountains and men's hat shops.

This fit of future-forward nostalgia was brought on by the launch that morning of Apple's new iTunes 4 with Music Store, an online service that lets you download songs for just 99 cents each and whole albums for $10.

Music Store will have a limited audience at first -- you need a Mac running the OS X system to use it -- but it's pretty clear now that the music industry is ready to give up on the CD.

Disembodied digital music has gone mainstream. For those of us old enough to still use terms like "record store" (I'm all of 31), this is going to take some getting used to.

Up to now, the digital music boom has been driven largely by the tastes of teenagers. Most grown-ups just don't have the time to skulk around online looking for "free" pirated music files with software like Kazaa and LimeWire. (At least some of us still have scruples about stealing.)

What's more, we don't want to listen to our music only on PC speakers or Walkman-like portable MP3 players; many of us have invested over the years in decent stereo systems.

We've also put a lot of money into our CD collections, and I for one am reluctant to abandon my CDs for anything that doesn't sound as good, or close to it. But the dirty secret about MP3s, the most popular new format, is that they can sound terrible -- particularly if you listen to jazz or classical or, really, anything more musically sophisticated than Britney Spears.

Still, going virtual is worth it. Over the past couple of months, I've tried out more than a dozen new digital music devices. I'm convinced that this new technology is something adults can love.

Related stories • Napster: Too legit to quit? • Giving iTunes a careful listen • Music biz ignoring adults

Apple's deservedly popular iPod is just the beginning. With a new breed of surprisingly inexpensive stereo components called digital audio receivers, you can now access your entire music collection anywhere in your house.

You'll even find that you listen to music in new ways. Recently the Talking Heads' sublime "Heaven" popped up on my jukebox in random play mode; I'd owned the CD for years but hadn't played it much and never noticed this amazing song. That kind of discovery happens all the time now that my music collection has been liberated from shiny plastic disks.

Ready to join the revolution? Here's what you need to know.

Digital music is nothing new, of course; all that's on a CD is a bunch of ones and zeros. What made the MP3 format so revolutionary was size. A typical pop song on a CD adds up to 30 to 40 megabytes of data -- enough to fill about 50 of those old floppy disks we used to use -- whereas an MP3 of the same music can be squeezed down to less than 4MB. That compact size is what makes it so easy to swap music over the Internet, legally or otherwise.

But the MP3 format also makes it easier to manage and listen to the music you already own on CD. Just download one of the popular free jukebox programs available on the Internet, such as MusicMatch for PCs or iTunes 4 for Macs (www.apple.com/itunes for OS X users; everyone else should look for iTunes 2, at www .download.com). These programs can read almost any CD and convert it to an MP3 in under 10 minutes.

Once you've put the songs on your computer's hard drive -- a newish computer should have room for hundreds of CDs worth of MP3s -- the software will play back your music in any order you choose and let you construct playlists with a few mouse clicks. You can also use the programs to make CDs or transfer music to a portable player.

No MP3 is exactly CD quality. To convert a CD to an MP3, the encoding software throws away sound data that the human ear supposedly can't hear. When this is done well, an audiophile might detect only the loss of ineffable qualities like "ambience" and "shimmer." Badly done MP3s, which make up much of what's on the pirate networks, sound muddy and thin. In some cases, you'll detect a soft but annoying sound I can only describe as swirly.

To create the best-sounding music files, shrink as little as possible. Most jukebox programs let you encode at a variety of bit rates -- the more bits, the better. I consider 128Kbps the bare minimum for music on MP3, and at 224Kbps my ears (admittedly damaged by my years playing bass in a high school garage band) can't tell the difference between an MP3 and a CD.

Trouble is, at 224Kbps my 3,000 or so MP3 files wouldn't all fit on my portable player, so I've compromised at 192Kbps. My suggestion: Spend a little time comparing different encoding rates with your own ears, using good headphones.

Both Apple and Microsoft already are pushing alternative encoding formats, which supposedly sound better than MP3s while taking up less memory. Microsoft's own WMA format already works with many MP3 players but not with the iPod.

Now, Apple's Music Store has complicated things further: Its 99 cent songs are in yet another format called AAC. So if Music Store takes off and sets the standard for online music, will MP3s become as obsolete as Betamax tapes?

Probably not. The latest iPods still play MP3s, after all, and there's no reason why any future devices couldn't work with all kinds of formats. Whether the current crop of non-iPod MP3 devices could ever be upgraded to read Music Store files is a murkier question because of Apple's copy-protection measures.

If you have a Mac and one of these other players and can't wait to try Music Store, there are some quick-and-dirty workarounds. I recently copied my Music Store purchases onto a CD and then encoded that CD into MP3. The results sounded fine. My guess is that soon either Apple will open Music Store to other players, or a competing service will pop up to serve the rest of us.

The most popular way to listen to MP3s is on portable players, and the iPod ($299 to $499) is still the best-designed product in this category, even forgetting Music Store. The new version weighs about six ounces and can store enough music to play without repeats for up to three weeks.

You can get players from companies like Creative and Archos for $100 to $200 less than the iPod with the same or greater disk space, but they'll be heavier in your hand and their on-screen interface for finding and playing songs won't be as elegant -- a problem when you've stored, say, a couple thousand songs.

Your portable player can also function as a stereo component. For less than $10, you can buy a cable from Radio Shack, with two stereo RCA plugs at one end and a headphone plug on the other, and run a player through any stereo with a spare input. The new iPods even feature a docking station with a proper "line out" plug to make this even easier.

I haven't found this solution satisfying. For a start, it looks messy to have all those extra wires hanging over the stereo rack. More practically, my not-especially-huge music collection would fill up two-thirds of the memory on even the most expensive iPod, leaving little room to add more over the years.

What I really want is a giant digital home jukebox. A few companies have tried selling stereo components or shelf systems with huge hard drives built in. Sounds like a great idea, but I tried several and found them either too expensive or too hard to use, and often both.

Here's a better way: Instead of trying to get your stereo to act like a computer, connect your stereo system to the computer you already own. If you have a newer machine, you probably have 30 or 40 gigabytes to spare on your hard drive right now, and adding even more storage capacity to a PC is cheap.

This doesn't mean you have to sit at your computer to fire up the music. A digital audio receiver, or DAR, can sit right on your stereo shelf or in your bedroom or anywhere else you want to listen.

The devices, which can be packaged as components or all-in-one stereo systems, connect directly to your home network, usually through an Ethernet port. (Some also come Wi-Fi ready.) They don't store any music; instead, they go to the network to find and control the music on your computer's hard drive.

DARs turn your computer into an entertainment hub, and you can link several DARs around the house to the same computer

Connecting a DAR to a network can be tricky, but once I got it, most of these devices were as simple and intuitive to use as a CD player.

Among the well-known electronics brands, Onkyo and Philips offer stereo minisystems with built-in DARs for under $400. I also particularly liked Slim Device's $229 SLIMP3, a small device with an incredibly sharp and easy-to-read menu screen for displaying song, artist and album names.

But the DAR that's still miles ahead of the competition is the Turtle Beach AudioTron ($300 to $350), which looks like a high-end stereo component. The array of buttons is simple -- play, pause, fast-forward and so on. And like the engineers at Apple (and almost no one else), Turtle Beach knows that when you're scanning thousands of song titles, spinning a wheel is just better than pushing buttons.

The AudioTron can run on both PCs and Mac OS X, though the company doesn't provide Mac support. It can catalogue some 30,000 songs, and it plays MP3 and WMA files, as well as uncompressed, true-CD-quality files for listeners with delicate ears and big hard drives.

What more could a grown-up music fanatic ask for?