I’ve used SnapZPro to record screen activity with audio (using a USB headset mic). One disadvantage is that it exports only to QT format (no Flash video flv option), so I started looking around again.
Since surfing takes less time than actual testing, it was quicker to make a list of links to other people’s experiences. The comments to blog entries offer lots of info too…
Products that get multiple mentions include ishowu and screenrecorder.
Here’s a nice list of screen capture software that gives an idea about relative cost and a quick summary of each. The article ends with head to head comparisons of some of the more popular programs, quite helpful info. [from labnol.blogspot.com]
And here’s a more complete review of many of the same programs. [from donationcoder.com]
Decisions, decisions! 
Nice list of different programs available for various platforms, including some one-on-one comparisons of the more popular programs.
http://labnol.blogspot.com/2005/05/screencasting-to-help-your-mom.html
