According to ZDNet, Nintendo Wii 2 will be released mid-2012.
"Japanese news organization Nikkei, however, may have accidentally leaked Nintendo’s news for them. A report from the organization this weekend confirms that the Wii’s successor will indeed have a touchscreen. Normally, a confirmation outside of an official one would be considered bunk, but this bit of news means something considering that it comes from Nikkei itself.
The report says that the controller’s built-in touchscreen will be six inches and that the controller itself will come with its own battery and a camera. Nintendo plans to release the console mid-2012, the report says."