The PEGI has now rated the game as well, however, and they've revealed that it is actually for WiiWare. Brain Challenge is similar to games like Dr. Kawashima's Brain Training for the DS - Basically, you take a few tests and see how smart you are. There is a whole plethora of ripoffs around, but reviews for Brain Challenge (Which has already been released on the DS and Xbox Live Arcade) have actually been surprisingly positive.
We're not sure when it'll hit WiiWare, but it's probably soon. Keep an eye out!