Screen Capture App???

I was wondering is there is such an app that can record what I am doing on the screen. Say... I wan't to record a movie on how to burn a disc, instead of a camera facing the screen can the screen record itself in a way? Any tips? Advice?

Thanks

EDIT: I think I found my answer in a earlier post.

there are a few programs on pure-mac.com that'll do that. i found a few that worked pretty good.

Screen Mimic seems to give the best performance.