What games and apps for 2 + 4yr-old?

[BelfastBloke]

Flying longhaul soon. I have an iPod touch (like an iPhone without the phone) that I can devote exclusively to the kids.

They haven't played with one before, but they're fascinated by the photos on my iPhone, so I know that it'll distract them for quite a while if I can get the right games and apps. Will practice myself before the flight, so I can train them up during the flight.

So, what games and apps for a 2yr-old boy and 4yr-old girl?

My 2 year old loves Tozzle. It's a jigsaw puzzle with about 40 puzzles.
Leo Stickers is another jigsaw one, but free.

I don't have a 4 year old so can't help there.

I turn the wifi off when she uses it as otherwise she's sending emails or trying to buy stuff.