The Microsoft Patterns and Practices Developer Center has released the Composite Application Block for WFP and Silverlight.

The Composite Client Application Guidance is designed to help you more easily build modularWindows Presentation Foundation (WPF) and Silverlight client applications.

These types of applications typically feature multiple screens, rich, flexible user interaction and data visualization, and role-determined behavior. They are "built to last" and "built for change." This means that the application's expected lifetime is measured in years and that it will change in response to new, unforeseen requirements. This application may start small and over time evolve into a composite client—composite applications use loosely coupled, independently evolvable pieces that work together in the overall application. Applications that do not demand these features and characteristics may not benefit from the Composite Application Guidance.

Read more about it at:  Composite Application Block

Download the VB Examples here.