One of the great (and only) new applications that comes with Snow Leopard is Quicktime X. Quicktime X has a multitude of enhancements but the one we've been most excited for is the screen recording.
I've created a quick screencast to show off the screen recording capabilities.
Ironically, you can't record a screen recording of a screen recording using Quicktime X so I've recorded this with ScreenFlow.
Here is the original Quicktime X recording:
The process is simple and straightforward. Open Quicktime X and select "New Screen Recording" from the file menu. Hit the red button and you're recording. When you're finished, click the stop button in the menu bar. The default save location is your Movies folder. Then you can view it, trim it, or upload it to the appropriate site whether that's YouTube, Facebook or your Wistia account.