Sony BMG has signed a deal allowing file sharing outfit Mashboxx to offer legal music downloads.

Mashboxx, CEO, Wayne Rosso, the former president of Grokster claims it is the world's first file sharing application with content authorised by a major record label.

Mashboxx, which was founded last September offers content searches by plugging into most of the major existing file sharing networks, such as Grokster. Because the service is designed to work with technology developed by Snocap, a company headed by Napster founder Shawn Fanning, when a Mashboxx user finds content on a file sharing site, this technology identifies songs by their digital 'fingerprint' and determines if it is copyrighted.

If it is and the copyright belongs to Sony BMG, then the Mashboxx user download request is redirected. They are then given the chance to download the track and can then preview it for a limited number of plays before deciding if they want to buy it. If they don't then the track is blocked.

If the music copyright hasn't been logged by a record label, the searcher can then continue to download from the filesharing site, giving consumers the best of both worlds.

Of course there is nothing to stop someone bypassing Mashboxx and going straight to a file sharing site. However, it seems no accident that the Mashboxx announcement follows news of the recent victory by movie trade body, the Motion Picture Association of America (MPAA) against Grokster. Record companies have been keen to harness file sharing technologies despite ongoing legal battles against companies such as Grokster.

Although it only has Sony BMG signed up at the moment, Rosso is bullish that other labels will join in. Negotiations are currently underway with other major and independent record labels and will be announced upon completion.

"Sony BMG has done the heretofore unthinkable: embrace file sharing. And in so doing has displayed great courage and foresight. We at Mashboxx are clearly overjoyed because this is a watershed moment in the evolution of the digital music marketplace. We hope it will be the harbinger of a brighter future for content owners, p2p technology and, of course, users," he said in a statement.

The Mashboxx application is expected to begin testing shortly and potential beta testers are currently being enlisted at the Mashboxx web site

The service will only be available in the US initially, with downloads costing 99 US cents, however it should be rolled out to the UK and Europe soon according to Rosso.