By the way, if you are interested in creating screencasts yourself, you have several options. I use Camtasia Studio, which costs about £80 for an educational licence with a £30-£40 headset to ensure good quality sound. Camtasia is great if you are creating a large number of videos as it allows you to do this very quickly. It also allows the addition of simple pan and zoom effects and editing if required. The generated videos can them go on the University's video server and you can pass on the web address to your audience. A while ago I put together a series of videos that might help you get started with screencasting using Camtasia Studio.
If you are only creating a few simple recordings, you are probably better off using a free web based service like Screenr, which also hosts the video and will post it to your Twitter account if you want to distribute it that way.
[Image by Sarahnaut]
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