Learning is Fun iPad Apps

We really are big fans of the iPad, the Learning is fun website http://www.ar-entertainment.net/learning/ipad.html has a ton of educational apps and you can try most of them out for free.
I like the graphics and the fact that the boys don't need me at all when using them, Isaac loves the dinosaur puzzle and Reuben the writing/spelling ones and the mazes. My boys play with them (2 and a half and a very advanced 4 and a half) but older children who visit also like them.