When the new "Grand Theft Auto IV" downloadable expansion pack is released next week, called "The Lost & The Damned," fans will be able to tag songs in the soundtrack to purchase from iTunes.

This marks a shift in strategy by GTA developer Rockstar Games, which previously had tapped Amazon.com as it's digital music sales partner. When the game first came out last year, players could use an in-game feature to ID any song in the soundtrack being played at the time. That list of tagged songs would then appear in a custom "Playlist" on Amazon's new MP3 service for fans to buy.

According to the report in Variety, the company has given no reason for the switch. The iTunes music store recently shifted to a DRM-free model. Rockstar executives in the past said Amazon's DRM-free status was a key factor in its decision to partner with the newer service.