DS loves Tozzle, it's a puzzle game, 123 Couting, Shapes, Tilt Thomas, Talking Tom, Talking Roby, Babies, Working on the Railroad, Sprout Player, ABC Train. He has a whole category to himself. It's amazing how intuitive the iPhone is, as soon as I got it, he knew how to slide, tap, etc...he's a master of the iPhone.
My DH created a drawing app for preschoolers called Kid Slate- it's free on itunes. My daughter loves it and most of the adults I know have "bought" it too and confess to playing around with it.
Re: XP: favorite iPhone apps for you and you LO
My favorite apps are:
my local grocery stores
Facebook
iheartradio
weatherbug
AbbleDabble (scrabble that you can play with others that have the app)
Period tracker (my cycles are never the same and I have started to keep a record so I can talk to my doc about them)
My kids like:
Angry Birds
ABC tracing (you can trace the letters with your fingers)
ABC touch (the give you a couple letters and ask you find a certain one)
Paper toss
Touch Hockey (air hockey)
Saving for later too!