New tracks for the multi-instrument music title are released weekly via the online PlayStation Store and Xbox Live Marketplace, where they are typically sold by themselves for $2 or in three-song packs for $5.50.

"The success of Rock Band downloadable content to date firmly reinforces our vision and its potential as a platform for music discovery," said MTV Games senior VP Paul DeGooyer.

The company pledged that Harmonix will continue its weekly release of downloadable content throughout 2008, with full albums, such as The Who's "Who's Next," slated to arrive within that time.

Bolstering its focus on downloadable content, Harmonix today revealed that the PS3 and X360 versions of Rock Band will gain an in-game music store by the week's end, allowing potential buyers to easily sort and preview the numerous available songs.