My grandchildren just love my Iphone. They love to look at my pictures and listen to their special playlists.
Several of the applications are just wonderful when I take the kids on the subway to keep them busy or at a restaurant waiting for our orders.
I recommend at the app store:
AllisJig Saw and iDoodle2 lite.
The jig saw puzzles are a little tricky so I would say ages 4+.
Doodle is good for 3+.
Both are open ended because I love them too.
The Doodle work can be saved to iphoto and the kids can admire their work.
I keep a special iphoto album just for their doodles.
Urban Granny