There's a song I heard repeatedly at gym I frequented a few years ago that came on at least once during every workout. But for one reason or another I still don't know its title or performer. How cool would have been if I could have automatically identified the artist and track name (let alone purchase the song) by simply taking out my cell phone?

That type of service would have been impossible then, and even still sounds a little far fetched today. Yet in Japan, a cell phone-based music identification solution is exactly what the country's number two wireless operator, KDDI, recently launched.

Called Listen And Search, the service lets KDDI subscribers use their 3G handset to automatically identify songs they hear (in a bar or on TV, the radio, etc.) and purchase that song as a ringtone, full song, or album. It is enabled by digital media management and content vendor GraceNote and BREW application developer MediaSocket.

The service works like this:

When a user hears a song he likes, he pushes a Search button (available on certain KDDI handsets) to find out more about that song. Listen And Search automatically uses Gracenote Mobile MusicID solution to retrieve a match from a Gracenote database and delivers its name, artist, and album to the phone. At the same time, Gracenote connects the recognized song to a commerce solution for the retail opportunities mentioned above.

Media Socket is responsible for integrating Gracenote’s technology into a BREW application. It also runs the client software and day-to-day operations of the service.

Listen And Search is available for three new KDDI supported handsets: the Toshiba W31T, Sanyo W32SA, and Toshiba A5511T.

An extended service called EZ TV is available on the latter two handsets, as they embed TV tuners. With EZ TV, users can identify music playing right on their phone as they watch TV on its display.

Both Listen And Search and EZ TV are supported by Gracenote’s global waveform database of 6 million song fingerprints, including a Japanese database that uses local popularity ratings to offer recognition for many of what it asserts are the most listened to songs in Japan.

The delivery of data services like music, games, etc. is the wave of the future for carriers who've seen their voice revenues drop considerably over the last few years. These offerings are also a substantial business opportunity for content providers.

For example, one of the largest music conglomerates in the world, the Warner Music Group, announced a deal late last year with Melodeo to allow consumers to shop, preview, purchase, play, and store download songs from its huge music catalog directly on their cell phones and smartphones.

The GraceNote/Media Socket solution one-ups the Melodeo service by enabling people to automatically identify the songs they hear, making it that much more compelling to consumers, operators, and content providers.

Unfortunately for folks in the U.S., most advanced cellular services like Listen And Search appear in Asia or Europe first before, eventually, finding their way to North America.