Apparently this service really works:

Shazam is a brand new service which tags music over your mobile phone anywhere in the UK. Just hit 2580 on your mobile and hold your mobile phone towards the music for 15 seconds after the tone. We will then end the call and you will receive a txt with the name of the track and artist.

Then you can come to this site and see a list of tracks you've tagged and buy the CD if you want. Your track list is permanent and free...

Shazam Entertainment has developed a breakthrough real-time song identification service for mobile phone users. The service is based on a patent-pending technology in audio pattern recognition. Shazam Entertainment´s technology is able to match a noisy audio sample captured on a mobile phone against a database of over a million tracks in less than one second. All we need is 15 seconds of sound. The search works even with background noise such as people talking or street noise, as long as the music is dominant.

Shazam offers its service to mobile operators, enabling them to drive premium service revenues with a killer music application.

Shazam's service works on any mobile phone without any upgrade to the handset or network.

Shazam Entertainment will also provide business-to-business services such as monitoring music and advertising on radio and television, ensuring that artists are paid royalties for public performances of their music.