ShowMe is an open online learning community where anyone can learn and teach any topic. The iPad app lets you easily create and share video lessons. Chicago Public Schools iPad pilot program teachers use it as formative assessment for daily math problems. Younger grades could use it one on one with parents or any grade to demo how to solve a problem and post it to a blog/tweet it, etc.
Create your own iPad app with this site. You can upload images, videos, text, and links- from what I can tell it likes a nice way to place content on the ipad in the form of an app.