As of late I have been looking into what ways that I could record a usability session of an application on a Mac. Windows definitely has an edge here with the Morae application from techsmith. This is a feature rich application that captures a usability session as well as make it easy to produce some nice reports. It captures both the screen and if you have a web cam, the subject. There is nothing equivalent for the Mac. However, there are a number of tools available for Mac OS X that can perform most of the functions of Morae separately.
For capturing the subject, since all Mac laptops and the iMacs have iSight built in there is no need for a separate web cam. All those machines usually have iMovie included which can capture the video. You can also use QuickTime Pro and stream the video to remote observation locations using QuickTime server. Then there are a number of movie capture tools listed below that can capture the screen events. If you are interested in just doing screen captures for documentation, and need functionality like snag-it (more than the default screen capture utility provides… like drawing tools, notation, highlighting) there are a few non-movie screen capture tools listed as well.
The following are a number of tools that can be used to capture the screen events on the Mac (Free and Non-Free);
For a list of more tools and short descriptions you can go here:
Last note: If you have an Intel Mac you can of course run windows and get Morae or just the Camtasia recording software from Techsmith.
Edit: there are a couple of new tools out there that I will soon do a write up. One is SIlverback and the other is Screenflow. Both of these are of the non-free variety, but they have the picture-in-picture capability that Morea does and are pretty nice to use.