If you are looking for a great role playing or digital storytelling app, this one is great. It is called Toontastic. It is FREE for a limited time, so hurry and download it!
I'm not sure who had more fun with the production of "Earth Threat"....my 6 and 4 year old kids or my 30+ year old husband! Productions can be uploaded to ToonTube and shared with family and friends via email, facebook, twitter, or embed code (the option I used to display the video below). The only negative is that you can't view ToonTube videos in iPad as they are FLASH, but the awesomeness of the app outweighs the flash issue in my humble opinion!