Jing is free software for screencapture ( both static and movies ), and available on OSX and Win32. See http://www.jingproject.com/ They will also give you a free account on sceencast.com to host your images and movies. If you need help setting up the synapse server etc, then you can use this software to do screen captures and you can then post them to their site ...
Jing allows you to record 5 mins of video. If you need something longer .. then CamStudio is also free software
