I just downloaded this app today and thought I'd suggest it to you mamas. I'm not going to post a link because it will be considered spam. I mentioned in my previous thread but I wanted to make a thread for it on it's own, because mommas were asking about it and I thought I might as well share with errrbody.
They have it in the Android Market and App Store. It's called Kid Mode by Zoodles. It is freaking great!
You set up an "account" for each kid, which they basically just click their picture and it opens up games and apps you specifically want for them. It locks it so they can't open ads or anything. It has games already on there too, and stories, paint apps, etc.
You can customize what things they are more focused on learning (math, science, cognitive skills, life skills, etc.) and they send you a weekly e-mail on your kids learning and progress. Block characters if you don't like certain ones (i.e. Elmo, Bob the Builder, etc.) It's freaking awesome. I seriously would have spent money on it because I love it so much but it's free. You can also record yourself reading the story books they have on there.
I love kid mode by Zoodles my son is only 2 though so he backs out of the games and gets mad at it from time to time so I also have an app called toddler lock that locks him on that screen so he can't get on the internet and it plays music when they are 'drawing' on the screen and if they just push the screen different shapes and colors come up.