Tony Reinke on Shazam for the iPhone:

For the music lover, Shazam is the single
greatest iPhone application I’ve seen to date. If you’re in Starbucks
and you hear a song being played, you open this program, it listens for
10 seconds or so, and then tells you the artist and song title. And
it’s free!

Download app for iPhone 2.0 here (iTunes).

Shazam!