Sony BMG, the final major music label to hold out against selling its catalogue of music as unrestricted MP3s, has agreed a deal with online digital music service 7Digital.

7Digital customers can now buy tracks from all four major music labels in 320 kilobits per second (kbps) MP3 format, free of digital rights management (DRM) restrictions.

Users who have purchased Sony tracks in the past in WMA or other DRM formats will be offered the opportunity to 'upgrade' their tracks to 320kbps MP3s by 7Digital, at no additional cost.

To coincide with the announcement, 7Digital is offering to give away two free albums to each of its customers: one featuring tracks on the Sony BMG roster, including Beth Orton and Doves, and the other featuring selected unsigned acts from 7Digital's Indiestore site, which allows less well-known artists to upload their music and promote themselves.

Separately, 7Digital announced a new partner programme and application programming interface (API) that will allow third parties to sell music on their sites using the company's infrastructure and catalogue of tracks.

Finally, 7Digtal announced that it has launched services in Austria, Italy and Portugal, and plans to unveil US and Canadian sites in the fourth quarter of this year.