The Office Labs at Microsoft gave us a nice (and free) product.
Community Clips is a free tool that can be used to do screencasts and help videos. It integrated directly in the quick access bar in office 2007 applications and can also be used outside of these applications with the tray icon it creates.
It generates very lightweight .wmv files and is really easy to use.
The opinions expressed herein are my own personal opinions and do not represent
my employer's view in any way.