Duck Duck Moose This site has links to apps that are great for math, literacy, nursery rhymes, play, and creating.
Khan Academy Kids Will personalize learning for your child - great for ages 2 to 6.
Endless Alphabet (plus more) Endless alphabet is so much fun (a bit pricey) there are others that are free on their site also.
Alien Buddies On this link the right hand side has more games that you can look into. My own children enjoyed Alien Buddies and Drive About.