Ever hear a song you like on the radio, on TV or at a party but don't know what it's called? Install Shazam on your iPhone and you can find out.

Whenever you hear a tune you dig, simply hold your iPhone's microphone to the speaker. Shortly after, as if by magic details of the song will appear in the Shazam interface, including the name of the song, the singer, and the album it appears on.

That's not all either, in many cases Shazam will provide a link to the song's video on YouTube, and offer the possibility to buy the track on iTunes.

But how can Shazam know so much about all this music? Well, Shazam 'hears' the song through your iPhone's microphone and uses your mobile Internet connection to compare the sounds it receives with those recorded in a huge online database of music. If it finds a match Shazam will provide you with the information immediately, and offers you the ability to email it to a friend if you wish. While Shazam can't recognize every song in the World, it managed to get most we tested it with.

Shazam now includes a Friends feature, which allows you to see what they're tagging, what they've bought, and what videos they're watching.

If you're a fan of music (and, let's face it, who isn't?) then Shazam is an essential addition to your iPhone.