Great for 4 year old
My 4 year old got this as a b-day present, has sat down, and can follow the pictures and directions well enough to just be reminded where to go. Pictures jump up to tell him if there is a button or an action he needs to do to complete a task. The races are a little difficult for him, but the game needs to be able to grow with him some too. Definitely a must have for young kids who want so badly to play Wii with their parents.

great for a first preschool game!
I bought this for my 2 1/2 year old granddaughter. I had to nearly pry the controller from her 2 hours past her bedtime. I only had to help her extensively for about 10 minutes or so then she caught on to pushing the button to jump and after 30 minutes learned how to go forward by herself. When they show her what to do, as in climbing or digging she caught on almost at once the first time. She is crazy about having her own game and being able to play it just like everybody else. I do have to help her some, but it is so much fun hearing her laugh and say "I did it!"

Great game for young children
This is one of the few great wii games available for young kids. My son is 5 and plays with it and sometimes says its too easy for him.

Perfect!
My daughter is 4 and absolutely loves this game! She figured out game play fast. I like the fact that there are little animations in the corner that show you what to do with the wiimote for certain actions, such as pumping up the hot air balloon or waving the elephants trunks to wash diego when he gets dirty. From what i've seen, there seems to be only one button that is ever pressed, otherwise its movements.
There is a race mode that you can play with 2 players. The races are short, but fun for kids. We've even raced! Also, a major point for us is that they don't make a big deal out of who wins there race.
The only thing adults need to be involved for in this game is helping with some menus, but they are few and far between!
If you have a wii and your child likes to try to play, than I think this game is perfect!!!

Great Wii Game for Kids
We bought a Wii a few months ago and have been looking for a good title for young kids to play. This game definitely fills the bill. The controls are easy to use and intuitive. To walk or run right, you simply tilt the controller to the right. To push an object, you push toward the screen, etc. There is also a feature that allows a parent to help with a limited number of tasks with an extra controller. Kids may like to see you help, but can generally perform the required tasks on their own, given the clear animated diagrams that appear to demonstrate the actions they should perform.

The game seems engaging for kids, and has the feel of a Dora episode, with a backpack appearing to dispense items, and a chain of intermediary tasks leading up to a larger goal. The one caveat I have is that I think many three year olds would be frustrated without a fairly large amount of assistance, but 4 to perhaps 7 seems like a good target audience. Older kids might become bored for the same reasons that the game works so well for younger kids: the tasks are comparatively easy, and the game is structured to prevent players from failing in any serious way.