GoNintendo has uploaded a scan from Famitsu, a Japanese gaming magazine. The image gives us insight that a SimCity game for the Wii is coming to Japan in September. This should mean that a few months after their release, the US should hear about it.

I cannot read or translate Japanese, but according to his post, WiFi will play a part in the game.  I uploaded the picture to UOEM, so head over there or click the image for the full size.