The developers of Ubuntu One, the next Ubuntu release, are apparently planning a music store along the lines of iTunes. More here

Among the newest Blueprints is one that may be a money-maker for Canonical. Developers of Ubuntu One, which is a commercial offering in and of itself, are planning a Music Store from which you can possibly buy music without DRM restrictions, much like Apple’s iTunes store. Because the idea came from the summit, it’s likely that the store will become part of the Ubuntu 10.04 “Lucid Lynx” release