I've long used screen captures to illustrate manuals and Power Point presentations. TurboDemo, while costing money, looks to be a good solution for computer lab instructors who need to introduce new applications and then test the students to how well they understand what they have seen. TurboDemo has the ability to capture the screen in a continuous mode and then have to provide a voice over and ending quiz.
I could see this application saving a tremendous amount of time at the beginning of each semester. It would also work well for helping distance-learning students learn the distance-learning platform. I find that it can take a week or more for a new student to learn the ropes of a new online learning system.