Just found this when stumbling around Nintendo's press site. I hadn't heard of this feature yet.
QUOTE said:Wii Fit Channel (available May 19): This channel appears on the Wii Menu when people first use Wii Fit™, which combines fun and fitness. It’s an easy way for every member of the family to keep active and play together. In a first for a Wii game, owners of Wii Fit can access the channel to perform basic daily workouts and fitness checks, even if the Wii Fit game disc is not inserted.