On TemplateMonster.com you can find some very cool Silverlight templates. Unfortunately they are not free, but you can check them anyway.
Silverlight templates are basically pre-made animated design products made with the Silverlight technology - a new solution from Microsoft. The templates made with this technology allow premium animation as well as a fair extent of interactivity available within the animation. Our Silverlight templates - as every other design product from TemplateMonster - are based upon our premium designs and are simply perfect for whatever the needs you may have.