Search for OpenSource, Creative Commons and Copyright Free music online:
Stonewashed has an index of the various sites sharing Creative Commons free to use music sources (check which licence applies to your piece of music)…
CCmixter has an excellent indexed method of finding music by genre and style…..
Jamendo Discover the 40992 albums available for free and legal download on jamendo….
Incompetech.com by Kevin MacLeod
The Internet Archive
note: you must select music which is specifically licensed under the Creative Commons as in The Public Domain