Good iPhone Apps for Kids

My four year old, Seth, loves to play with my iPhone. He's pretty computer-savvy for a four year old and he is therefore good with the iPhone. I've found a few nice little apps for him and I thought I would share. I'm doing this for two reasons: (1) because I needed an idea for a blog post, and (2) in hopes that someone posts some other good ones to get him in the comments!

One thing: I only want FREE stuff. I'm not spending cash for my four year old to play with my iPhone. Sorry.

Here's what I've tried:

1. Trivial Memory Christmas - A memory game with Easy, Medium, and Hard levels. Fun :)
2. iXmas Tree - You get to actually drag and drop the balls, garland, etc onto the Christmas Tree
3. i Say Free - Sort of a follow-me app - like the old Simon game
4. Christmas Lights - This is just an okay game; not great but it is free!
5. TicTacTouch - what kids doesn't love to play Tic-tac-toe?
6. Crazy Pumpkin - a great app that he can shake and swipe; makes pumpkin jack-o-lanterns fun
7. Singing Pumpkins - is what it says... You touch the pumpkin and it makes singing sounds. Cute :)
8. FourFree - Basically Connect Four
9. DigiDrummer Lite - a fun digital drum app

As you can see, the holidays are well represented (it is December right now).