1. The 1st half of this article will compare and contrast MVC, MVP, and MVVM, and suggest which pattern to use based on your technology of choice and the problem that you are trying to solve. The 2nd half will be an overview about how MVVM could be used in Silverlight.
2. Model-View-ViewModel (better known by its super hero alias of MVVM ) is a great pattern to use with Silverlight and WPF. Here is a 5 minute perspective on MVVM.
1 reason MVVM works really well with XAML based applications is because of the powerful XAML binding features. This allows the View (the presentation of to the user) to be separated from the data and the logic. The View can be designed in Expression Blend while the ViewModel can be developed in Visual Studio .NET. It allows for the presentation to be separated very easily. This is just 1 reason, albeit a powerful one.