The full 83 minutes of my PDC talk are available on the Channel 9 web site. You can watch the session online (using Silverlight) or download the video in a number of formats. Slides and source code for the demo are also available.
Another talk you may be interested in is Stephen Walther's. Stephen did an amazing job explaining how jQuery and ASP.NET Ajax work and fit together. The talk is very accessible even if you have no prior knowledge of jQuery: http://channel9.msdn.com/pdc2008/PC31/.