MVVM resources

There are probably more than 10 different implementations of MVVM. For example, just to list a few:

1) http://code.msdn.microsoft.com/WinFormToWPFMVVM

2) http://karlshifflett.wordpress.com/2010/11/07/in-the-box-ndash-mvvm-training/

3) PRISM -http://msdn.microsoft.com/en-us/magazine/cc785479.aspx-

Personally, I like Karl's implementation; it's really well documented and easy to understand.