probably, one of the most useful apps out there. If you like music in a cafe and you don't know who's the artist/title, Shazam will definitely help!
Shazam is an app that lets you find a song's information — including title, artist, album name, and more — by simply setting the program to "listen" to it. The app then searches through its extensive database to locate the data and present it to you in a clean and simple way. It also displays on-the-minute/up to date/current information about your favorite artists, like when they will be on tour and where you can catch upcoming concerts near you.
The app is completely free of charge.
The Shazam app is also available for Blackberry mobile phones and for iOS devices.