Earlier this year, I gave a presentation about using Blend to create Silverlight applications at TechEd with another member of the Blend team, Unni Ravindranathan.  You can see a video of the presentation here: http://www.msteched.com/2010/NorthAmerica/WEB201.  Unni and I discuss some of the new features of Expression Blend 4, and I walk through a demo creating a photo viewer application using some of these new features.  I've gotten some requests for the code, which I'm posting.  I've attached both the original projects that I started the demos with, as well as the final version after the demo.  There are two steps, the first is representing a designer -> developer workflow where the designer creates the application skeleton, and a second step that represents the developer -> designer workflow, where a designer adds some interactivity and hooks up to a predefined data model.

If you want to reuse the code or the demo content for your own presentation, please feel free to do so.