Trivantis Lectora Publisher. Can publish to HTML5 for mobile learning. They also offer Lectora Inspire which includes TechSmith Camtasia, SnagIt, Flypaper and Snap. http://www.trivantis.com
These apps are free and allow the user to draw and write free-form on the iPad screen as you might do with a Tablet PC. The ease of use of these two apps makes screencasting a possibility for the iPad. It would be very easy to turn out a quick screencast for a class. Limitations include a lack of options for exporting video. Screenchomp only exports to Facebook, and EduCreations only connects with Facebook or its own third-party video hosting service.