Harmonix confirmed today that Rock Band for Wii will be released on June 22nd for $169.99 [£85]. The so-called "Special Edition" bundle will include the game, drums, microphone and a wireless guitar. Standalone instruments will also be available for purchase on June 22nd. The Wii edition will feature 63 songs, including five unspecified "bonus" songs. We've asked Harmonix to answer some of your more burning questions -- we'll update this post when they do.
[Update: Sean from Harmonix dropped into the forums to answer some questions about the Wii release. First, "the feature-set is a lot closer to the PS2 version of Rock Band which was also developed by Pi Studios." Harmonix "decided to focus on getting the core gameplay on to the Wii and focus on making that awesome" which means we're expecting the same or similarly scaled-down World Tour and character creation modes. He also says "the instruments don't use the Wiimote. They function the same as our peripherals on the other platforms." Still no word on whether or not your existing Guitar Hero III Wii-guitar will work with Rock Band on Wii.]