http://www.shazam.com
I am sure this has been done in many places before, but Shazam appears to be getting very clever. For those that haven't tried it, it is phenomenal, call the number 2580, point it at your music source, 20 seconds later the name of the song is texted back to you. It seems to be best with electronic music.
http://www.shazamentertainment.com/technology.shtml