EDUcreations is not only a free iPad app, but also a web-based tool that teachers and students can use to record videos of "whiteboard-style" content. Below is an excellent example created by Canisius Grad Student Nicole Smith in EDT 505. In Nicole's lesson she is teaching us about QR codes.
Can't see the embedded video? Watch here instead.
About the Education Technologies and Emerging Media Program at Canisius College: