Name That Tune, in One Call

If you've been in a British pub in the past year, you may have noticed people holding their mobile phones in the air. No, they're not showing off the latest handsets; they are relieving that most annoying of musical itches: the oh-so-familiar-but-hard-to-identify tune.

Thanks to a mobile-phone service called Shazam, you can identify almost any song you hear — be it in an elevator, at a bar or in a mall. Just dial 2580 (in the U.K.) on your phone, point it toward the source of the music, and within 30 seconds you'll get a text...