PlayStation 2 owners were bummed when they had to wait an extra month for the greatness of Rock Band, but that's nothing compared to the seven months Wii owners have had to endure. Despite the lengthy period between the release of the PS2 and Wii iterations, the two games are mostly identical to each other. The Wii doesn't have online play and lacks most of the customization options of the PlayStation 3 and Xbox 360, but it still lets you and three friends form a band to rock the night away--and that's the important thing.
Rock Band includes a wireless guitar, drum kit, and microphone. The game supports a second guitar for bass parts, but you'll have to purchase it separately (FYI: the Guitar Hero 3 controller doesn't work). To use all four instruments at once you'll need to plug the included USB adapter into the Wii and then hook the instruments and wireless dongles into the adapter. For a detailed breakdown on how each instrument works and gameplay specifics, refer to our review of the PlayStation 2 game here. Other than the drum kit now being white and the pads feeling a bit softer and bouncier, there doesn't appear to be much of a difference between the Wii hardware and other versions--the instruments are responsive and feel great. While we experienced no problems with the hardware during the course of reviewing the Wii game, it's worth mentioning that previous versions of Rock Band have had issues with hardware reliability that often weren't initially apparent.
Source : Gamespot