I have been wanting to get a better handle on development using MVVM with WPF & Silverlight and trying to find good educational material. One book I have indicates using MVP but for the UI portion to use MVVM. What? That is confusing, then why have the M or VM?

I saw what looks like a good book on this coming - "Pro WPF and Silverlight MVVM: Effective Application Development with Model-View_ViewModel" by Gary Hall (an Apress book) but it isn't scheduled to release until October.

What or where is all the good stuff for learning the best practices to implement MVVM with WPF?
Thanks a bunch.
Tim