Locked down application

My daughter (2) is really interested in our Mac. We got her a really cool kids keyboard and mouse, virtually indestructible and water-proof. I'd love for her to be able to type and see letters on the screen and such, but her mouse allows her to click anywhere and open other apps, etc. We have Word and I've been using that to use big fonts for her, etc.

My question is this... is there a good application that I can set to require a keystroke combination to "unlock" the application, or maybe just a full-screen application like this for her to use?

Also, any other young developmental kinds of games you can suggest would also be awesome!

Thanks!

Kids Mac Educational Software And Learning Programs - OSX Compatible

31 Top Kids' Software Titles | Mac|Life

just a few sites ive found, hope this helps

Yes. You could actually create a parental controlled account, and basically lock down the account in every way possible, only allowing the applications you choose to be opened.