Fred - I don't know about you, but I have to get these things done. I spoke with one of the Techs @ Vandy, where I'm in a grad prog, so you know I need to get this done! He sent me to <
http://www.ambrosiasw.com/utilities/snapzprox/> where I downloaded the free version of the prog. It does a great job of recording what's on your screen and your voice from the on-board mic, and converting it to a quicktime movie. It takes up a bit of space, so you have to play with frame rates and mono vs stereo, but it sounds as good and should work (as long as no one needs to see your powerpoint notes).
This is the best I've found so far.