I've produced a screencast of using the multihead stuff I blogged about yesterday. A couple of things to mention. I'm using an external CRT Iiyama monitor but it could be a projector for doing a presentation. Also, I have Screen Resolution added to my main menu to speed the process up - you can find it in Control Centre if you have the packages from Federico's project installed.

multihead-screencast.ogg (Ogg Theora, 6.3M, 4min 39sec)