MelodyCatcher - Melody Catcher: The Internet Music Search Engine
Shazam - Shazam is a mobile app that recognizes music and TV around you.
Pollux - See related links to what you are looking for.
SoundHound - SoundHound - the most immersive music search, discovery and play experience on mobile.
TuneUp - TuneUp makes your music fresh and clean!
Musixmatch - - World’s Largest Lyrics catalog and official