This is a link to a 5 minute video on MathCasts

MathCasts are ScreenCasts (videos) that focus on math from both an instructor and learner perspective. An instructor can produce a video that shows step-by-step the process for solving math problems. Even more interesting to me, is using MathCasts to capture the learner solving a math problem step-by-step. The equipment requirements can be as much as $300, but with headphones and mics becoming ubiquitous and cheaper, open source software for screen capture maturing; and other hardware going down in price, perhaps this can scale.