For WPF, the MVVM pattern is so deeply ingrained in the framework itself that you don't really see it until someone points it out to you. You don't really need a separate framework for that (although certain types, such as Josh Smith's RelayCommand, would be nice to have in the BCL).
Windows Forms isn't really going anywhere anymore, which is why you don't see any new or thriving MVC-style frameworks for that platform. However, patterns & practices' Composite Application Block (CAB) was an attempt at such a framework.
Most people found the CAB to be too complicated to their taste, but I personally found it a valuable effort, even if it could have been simpler to use. It's still out there and available in source code format, so you might want to take a look at it.
However, if at all possible, implement your application as a WPF application instead.