Model-View-ViewModel (MVVM) has been introduced to me around March, 2009. This is the suggested patter to use to fully gain the benefit of the binding capabilities of Silverlight and WPF.

I have found a very nice tutorial of Jason Dolinger that discusses this pattern. Here is the link:

http://www.lab49.com/files/videos/Jason%20Dolinger%20MVVM.wmv
http://blog.lab49.com/archives/2650