The other day I learnt exactly what you can use Viddix for! (www.viddix.com.) Viddix is a unique movie sharing site where there is a double screen, one of them the movie of you talking, and the other can show supporting text or pictures! Our class is using Viddix this term, because we are all going to write a fairytale.
The first step is to make a movie clip using i movie, Photobooth, or anything else that can convert your clip into a Quicktime, to be uploaded to Viddix. The rest is quite self explanatory.