Interesting but the video is a good demo of "how not to film a presentation" but its still watchable.
http://video.google.com/videoplay?docid=4762944544960468107&q=flex+flash
For those of you interested in getting involved on the GUI end, James has done a really great job of prototyping out a basic webmail front end (see jboss-mail/src/flex), this might be a good jumping off demo...though a little hi on the hype.