The Visual State Manager is on a very short list of features that exist on Silverlight today but do not exist on Desktop WPF. This short screencast introduces the Visual State Manager and illustrates the value it adds to the Silverlight platform. It shows how the Visual State Manager can be used in control templates as well as full application screens.
John Gossman from the WPF team blogged that the Visual State Manager will be added to WPF in the future. He has not indicated when an officially supported WPF version will be available but he did supply a working sample that is compatible with its Silverlight 2 Beta 2 counterpart.