Don't know if this is what you are looking for, but the wii has some games that are only directed towards younger kids.
UbiSoft is releasing a a point an click adventure game /with 15 minigames. It's called "Cosmic Family". http://www.gamespot.com/wii/action/c...45&mode=recent
And also if you are looking for something a bit more educational, there's many learning-based games designed for the wii that you can access through the opera internet channel.
Here's all the ones I know of:
Arcademic Wii Games - http://arcademic.altec.org/wiilist.htm
Multiplication Games - http://www.gamequarium.com/multiplication.html
Weekly Reader Games - http://weeklyreader.com/kids/games/