Pandora.com is an incredible site that helps you discover new music. You tell it the title of a song or name of an artist, and it will create a station for you, starting from that selection. Pandora then plays a song from a similar artist that it thinks you'll like, as it builds a custom net.radio station for you. The Long Tail Blog says,
"[T]hey determine similarity not by what other people listen to but what their small army of musicologists identify as related traits in the music itself. You'll get delightful stuff you never would have thought of."
I started with Soul coughing, discovered a band called Gerling, heard an old TMBG song I'd somehow managed to never hear over the years, and eventually heard a new band called The One AM Radio (which I LOVE, and never would have found on my own, which is the whole point of Pandora.) If you really like a band, there are links to Amazon or iTunes so you can buy the album, or explore more of their stuff on your own.
Pandora gives you ten hours of free listening to try it out, and offers a year of service for thirty-six bucks. If pandora can stay honest, and keep the music industry's pay-for-play agenda out of the way, it could be an amazing service.
(Thanks, Carsten!)