Screenium... Make live movies of your Mac's screen, capture everything happening on your Desktop, in application programs, including mouse pointer, selections and movements - in real-time! Screenium even grabs live content streamed over the Internet. You can actually capture movie-in-movie: Screenium records your screen just like it is - including ongoing video playback in multiple windows.
With on-the-fly voice recordings, you can easily describe what you are doing on-screen. Simply use the built-in microphone or any external audio source or input device connected to your Mac. Screenium supports an unlimited number of audio sources, simultaneously, and in more...

WHAT'S NEW
Version 1.5:
Compatible with Mac OS X 10.7 Lion
Greatly improved tool to select the record area
Improved handling of external audio interfaces with more than two channels

REQUIREMENTS
PPC / Intel, Mac OS X 10.4.11 or later.