Do you have an MVVM-based Windows Phone 7 application and you don't like having to hook into the RootFrame to navigate between pages? Do you wish you could just "ask" to navigate to a new view from your view model? One possible solution can be found in my new Channel 9 screencast.
Using an message bus to process navigation messages, view models can publish messages that are then handled by a separate navigation service, successfully decoupling your view model from the Windows Phone navigation service.
Get the finished source code here