Rating Control with Theme Support
"If you play around with the toolkit you will quickly stumble on a new assembly called: “Microsoft.Windows.Controls.Theming”. In a nut shell what this class does is give control developers access to the ability to theme their controls. One of the key elements of this assembly is the “ImplicitStyleManager”. This class exposes some attached properties that allow designers to specify an external resource file (.xaml) containing styles which can be applied to a control and each of the controls children.
Here is what i did to get my RatingControl to use the implicit style manager. First I added a reference in my page.xaml to the Theming namespace." [More]
http://joel.neubeck.net/2008/11/ratingcontrol-theme/