If you have music on MySpace, you probably haven't read the T&C, although you should. MySpace now owns the rights to your music, to do as they see fit, including using it in commercials or on compilations without owing you a penny. Enjoy!
http://blog.myspace.com/index.cfm?fu...b-d75cc2a65170
http://blog.wired.com/music/index.blog?entry_id=1510286