When the PlayStation 3 launched, it attempted to upscale PlayStation 2 games, but Nintendo has stated that they won't try anything similar with the Wii U.
The news comes after Giant Bomb spoke to Nintendo's head of PR, Mark Franklin. He confirmed that the Wii U would not support upscaling for Nintendo Wii games - they will look exactly the same as they did before.
This might come as a disappointment to some, but many Wii games were designed with graphics that make them look just fine on an HD TV anyway.
Source: Giant Bomb