Since any decent tune I might want is copyrighted you shouldn't find it out there. What country are you in and do they allow this?
Few days back I was searching for something for music share and i found one good site name uPlayMe.com which helps me to find new music and share music with others.
Well still I am unable to explore this to my satisfaction.
May I request you all to please explore this fascinating music sharing community and suggest few things on this.