Here's a quick look at some of the skills you'll learn in the free online course over at Modern Lessons. It's a fun little side project I've built in an effort to make learning about education technology a bit more organized.
How to create ePubs from web-based content on an iPad
How to create and annotate PDFs on an iPad
How to record audio using your iPad
How to screencast from your iPad
How to curate teacher and student content from the iPad
Create account, create class, find/create rubrics, score rubrics and add comments, share with students (some iPad compatibility - no app - use through Safari)
Seems like ShowMe or Educreations and maybe a bit like Inkflow but with a pay version that allows for more control over your recorded whiteboard (pan and zoom). Pricey $8.99