"Indy is a music discovery program that learns what you like, and plays more of it. And it's free."

Indy.TV says this about itself:

Indy is a music discovery program that learns what you like, and plays more of it. And it's free.

Indy makes it easy for you to find great new independent music. Just download Indy and double-click: as it plays songs, you rate what you hear. Indy quickly learns what you like and gets really smart about sending you more music you'll like. Let Indy help you find your place in the collective consciousness as you help other people find theirs.

TidBITS had a good write-up on Indy that piqued my interest - including this:

What's particularly cool about Indy is that it's not attempting to maintain a centralized archive of songs, nor should it in any way run afoul of the jack-booted thugs of the recording industry. That's because, as I noted earlier, all the music is submitted by copyright holders, and because it's served directly from the artists' sites. In other words, Indy is a completely legal front end for discovering music you're likely to enjoy from all around the Web. At the moment, Indy knows about 10,000 songs, which should keep you busy for quite some time.