Hi!
I've just downloaded Expression Blend 3 from DreamSpark (for free because I'm a student :)) and read about states. I came across this and I was very impressed. And then I tried it on my own, I created a style, created a template, simply selected a button - but I cannot make those default styles like MouseOver, Pressed, etc. appear in the states window. Can someone give me a step-by-step beginner tip for that?
The VSM only works on Silverlight at the moment. It will be in WPF in the .NET 4.0 release (and is in the beta).
Right now in WPF, you may want to use DataTriggers. In Blend, simply edit your style, create a new Trigger and add the IsMouseOver property and set up your style for it.
If you download and install the WPF Toolkit (June 2009 Release) you will be able to use the States and Parts model in WPF.
You can download the WPF Toolkit at CodePlex: http://wpf.codeplex.com