We just created a page on Codeplex that will help you learn more about Prism (Composite Application Guidance for WPF and Silverlight) through videos and blogs. We currently have 6 videos for Prism 2.0 listed on this page. Please reply to my blog and let me know what other video's would be helpful to you.
The video's are divided into Overview and How Do I.
How Do I:
Bob and Erwin put together a series of videos that tell how to modular Silverlight Application. For more information see Bob's blog.
You can download the source from here for this application from the Codeplex page.