I just found 2 great white papers that briefly touches on the new features in WCF and WF 4.0 from a developer perspective.

 Check them out!

 WF 4.0

http://msdn.microsoft.com/en-us/library/ee342461.aspx

WCF 4.0

http://msdn.microsoft.com/en-us/library/ee354381.aspx