Channel 9 just published a Silverlight 4 Training which includes hands-on-labs, a video and a whitepaper designed to help you learn about the new features in Silverlight 4 !
The training is focused on three major areas:
Enabling Business Application Development
Empowering Richer Experiences
Moving Beyond the Browser
Silverlight 4 now includes cool features like Printing, WebCam and Microphone support, custom right-click, rich text, HTML support and access to local files with trusted applications.
Check it out over here