[acangiano]

On Mac OS X, one of the easiest programs to record screencasts and to do some editing, is ScreenFlow. On Windows, Camtasia Studio is definitely the best option, granted it's fairly expensive. On Linux, recordMyDesktop is one of the nicest programs, and of course it's open source and free of charge.

[nitrogen]

There's also the free CamStudio for Windows. The UI is clunky, but it works pretty well.