Shortly after news broke that Warner Music Group would not license its music to Nokia's new mobile music service, rival mobile phone manufacturer Sony Ericsson announced plans to launch its own mobile music site by the second quarter of next year.

The service will be an extension of the existing PlayNow initiative, which offers ringtones, wallpapers and full-song downloads to Sony Ericsson users. Full song downloads are limited to Sony BMG tracks. The expanded service will include a library of 5 million tracks licensed from all major music companies as well as indies.

The company also said it will integrate the download service with its other music-related services, such as the TrackID song identification functions. It also plans to add games and other content to the service.

L.M. Ericsson, one of the companies that makes up the Sony Ericsson joint venture, also provides the technology behind the Napster Mobile service.

The announcement comes as Sony Ericsson introduced three new phones-two additions to the Walkman brand of musicphones and a separate device optimized for mobile Internet usage.