So, it turns out you can record a VNC session as a Flash video  but it takes some work.
The first step is to install X11 and the X11 SDK on your Mac. This actually was harder than I thought it would be. The Mac pages say it's "on your Tiger DVD". Hm. That's kind of like saying the Indian restaurant you want to go to is "in New York City."
So, after a lot of Googling and poking and false starts, I figured out how to do it without having to reinstall Mac OSX completely (I balked when it said it wanted to reboot my machine and start the install process).
- Put DVD 1 of Mac OSX Tiger into your DVD drive
- The contents of the DVD should pop up in Finder
- Double-click on "Optional Installs.pkg"
- Skip past the Introduction, the license agreement, and select a location. Don't worry, it won't start installing
- You will see the "Installation Type" dialog
- Open the Applications node, and check X11
- Click Install
You also need the SDK. That's somewhere else entirely, but on the same DVD
- Open "Xcode tools"
- Double-click on "Packages"
- Double-click "X11SDK.pkg"
 I could not get this approach to work for me. The performance was godawful slow. What I have done instead is I got the recommended screen recording tool, Snapz Pro. This seems to be working great, although the movie size is a concern. Once I get this all working, where I can record a telephone conversation combined with a VNC session, I'll let you know how I did it.