According to a support question on the Red Octane website, Guitar Hero 3 will be heading to the Wii as well as the PS3, PS2 and Xbox 360. It has been strongly rumoured that Guitar Hero II would be released on the Wii and while that prediction may still happen, the third iteration of the game is now expected to launch later this year. No other details were given but as soon as we know more information we’ll be sure to tell you..
Source: Red Octane