ScreenChomp is a free app for creating and sharing short tutorials or lessons on your iPad. ScreenChomp provides a whiteboard on which you can demonstrate things by drawing and talking people through your instructions. ScreenChomp records your voice as you go. When you finish your recording share it to ScreenChomp.com where a shortened URL will be provided for you to share with anyone you like. From ScreenChomp.com you have the option to download recordings as MPEG-4 files.
The killer feature not mentioned here is that ScreenChomp was created by TechSmith. They make SnagIt, Jing, and Camtasia Studio. ScreenChomp can actually export .camrec files that can later be edited in Camtasia Studio. Oh, and ScreenChomp is free.
This is a game-changer in the whiteboard app scene for me.