The WPF team has just released an MVVM Toolkit which contains an overview and walkthrough of the MVVM pattern, a full Messenger sample app using MVVM, as well as a Visual Studio template for MVVM.  The template creates a WPF application with folders for Views, ViewModels, Models, and Commands.  What I really like about it is the DelegateCommand class which is similar to RelayCommand.  One addition to this version of the Command implementation is the ability to manually control when OnCanExecuteChanged is called or let the CommandManager control it.  The common scenario will be the latter, but allowing the option for the former will allow greater control over application performance due to the many calls to OnCanExecuteChanged.  In the future, the plan is to get this as well as other MVVM concepts into the WPF framework.  You can learn more about it here and download it here.  Check it out and we would love to hear your feedback.