Amazon List of 500+ Free MP3's

Amazon has a lot of free MP3's on its site. A lot of stuff I never heard of, but some aren't a bad addition to your library.
You can listen to a 10 second preview of each song right from the list. To download Amazon songs, you have to install the Amazon MP3 Downloader. It's a small program that will manage you Amazon downloads and automatically add them to your iTunes or Windows Media Player library.

See the list here:

Amazon 500+ Free MP3's