Joe Stegman and Mike Harsh presented 2 part overview session about building RIA with Silverlight. Joe did part 1 about Networking, XML, Data Binding and Controls. Mike covered Custom Controls and Layouts, HTML Integration, Isolated Storage and Deep Zoom features in his Part 2. Mike has also posted samples from his talk on his blog.
Ed presented on Video features in Silverlight 2.
Here is Steve Ballmer and Guy Kawasaki