The best of these sites is Listen.com, with listings for more than 130,000 artists. Listen.com does not give you the files directly. Instead, it points you to other sites, such as EMusic and CDNow, where you can find them. All five major record labels have invested in Listen.com, so you can be sure that every song is authorized. The majority of the downloads are free, the site is easy to use and the selection is impressive. Type in an artist's name at Gigabeat.com, and you'll get a similar list of websites, but not all are authorized. Gigabeat will, however, remove questionable listings if asked.

If you aren't looking for a specific song but just want to browse, check out one of the music portals. Surfing these sites feels like wandering through Tower Records — you'll wade through aisle after aisle of Top 40 superstars, but you may also find a lesser-known gem or two. The best of these is AtomicPop.com. It divvies up the downloads into free and paid and clearly marks which format the files are in: MP3, Liquid Audio or Windows Media. You can also find discounted CDs. Search for the legendary Pakistani singer Nusrat Fateh Ali Khan, and you'll get downloads as well as a link to a five-CD set for $25. Or check out EMusic if you have room on your hard drive and time to kill. For $10 a month, the site lets you download as many files as you want. EMusic feels a bit cluttered, though, and you can't listen to free samples.

DownloadsDirect.com, part of the Artist Direct website, is a huge digital music smorgasbord. The site looks chaotic, but you get a bit of everything, from major-label superstars to unsigned gems, with free samples of every song.

If you want to hear what the experts say before downloading, SonicNet.com is a good place to start. This site's strength is its editorial content, and it's choosy about downloads. Instead of offering every song under the sun, it features a few artists and gives you detailed information about them. MTV owns SonicNet, but the site's writing is smarter and more sophisticated than much of what you'll hear on MTV.

For niche music fans, there are websites that indulge your obsessions. Epitonic.com features punk, electronica, hip-hop and 20th century composers, and everything on the site is free. Eritmo.com is the place for Latin music. Songs.com focuses on country and acoustic music; free samples are all you get of a country queen like Emmylou Harris, but free downloads are available for lesser lights. RapStation.com is a hip-hop site with a strong political bent. All downloads are free, and the selection is vast, from rap superstars to up-and-comers. But with no paid downloads, it excludes artists who don't believe in giving it away.

Record labels have also recognized the promotional power of digital music. EMI plans to launch a subscription service this fall, while BMG and Universal promote their artists at GetMusic.com. Sony plans to have a digital service by the end of the year. Meanwhile, unsigned artists push their MP3s at sites such as Hungrybands.com, Vitaminic.com and 818music.com.

None of these sites has the tremendous reach of Napster, with millions of users generating an ever-expanding database of songs. After all, there was only one Elvis.