A great software demo; tools for creating demo movies

I enjoyed watching the Ruby Rails demo that is a 10 minute demo of building a web application using Ruby Rails. This demo was made by capturing a video as the demo creator smoothly went through the steps to build a web app.

I have looked at a few Mac OS X demo-making to Quicktime movie products and I think that I will make my selection soon. I am motivated to do this for a few reasons. One of my customers is interested in ways to demo the web application that I developed for his company and creating a demo like the Ruby Rails demo seems like a good idea. As bandwidth gets cheaper, I have also thought of augmenting the free web books (on my main web site) with free instructional videos.