Is there a free music site?
Not exactly, but there are mp3 spiders out there that help you find them.
(I don't recomment limewire, since the default configuration has your system acting as a server, which is generally illegal).
hyooge.com is one that seems to work well without trying to annoy you to death. You have to have an account, but accounts are free.
its not free but illegal www.limewire.com