The Hype Machine searches the web for websites and blogs featuring music tracks of your chosen artist or versions of a chosen track. It compiles what it finds into a playlist, which you can play in the media player of your choice. And even better – you can save your search as an RSS feed, updating when new music is found.
I’ve tried various searches, from the obvious to the fairly obscure. And as you would expect, you get more success for obvious names, but you do get better-than-expected results for more unknown acts. Playback is good, but dependent on the person uploading the file. Still, it’s not a bad way to hear the music you want without paying out for a download or subscription.