Kohit.net is one that I know. But I can't pledge that it would be legal. I agree with others, I don't think that there are anything which would be legal and free. Except those garage bands. I also know a site which is full of those garage bands' legal music but I reckon that there are a language barrier which prevent you to use it (if you still wan't to try, the web site is http://www.mikseri.net
I've understood that LimeWire is legal but the music isn't. Except if you load something which have put on the list legally.