Guitar Hero: Greatest Hits will appear on PlayStation 3, Xbox 360 and Wii, bringing full-band versions of major songs that have appeared in past guitar-only iterations. Greatest Hits marks the first major Guitar Hero title to not appear on the PlayStation 2.
Update: Activision has since announced Greatest Hits for the PlayStation 2.
Both Greatest Hits and the new Nintendo DS game will arrive over the summer. That Nintendo DS game is likely to be Guitar Hero: Modern Hits, which has been previously revealed via trademarks and listings but never officially confirmed.
In addition, Activision Publishing president Mike Griffin revealed that the company is planning a "major re-stage" of the franchise with "all new differentiated Guitar Hero products" in the second half of the year, presumably in the fall holiday season.
The three Guitar Hero games join Guitar Hero: Metallica, which hits PlayStation 3 and Xbox 360 on March 29, followed by PlayStation 2 and Wii editions later on. Activision is also planning to debut the spin-off DJ Hero franchise at some point in 2009.