A few weeks ago, I started to build what will hopefully grow into a larger library of screencasts covering Windows Presentation Foundation ("Avalon"). The first two have just been posted on Channel 9.
Screencasts are short pre-recorded videos that aim to show succinctly how you can build cool stuff using Avalon. They start with an introductory slide to cover the concept and then dive straight in to a fast-paced demo.
Introduction to XAML demonstrates how you can embed all kinds of content in XAML and integrate them together.
Data Binding in Windows Presentation Foundation shows you how to build an RSS browser in just 14 lines of XAML using the data binding features present in Avalon.
I'm pretty proud of these, and I hope to produce more if feedback is positive. Let me know what you think!