Applying simple 3D effects (a.k.a. perspective transforms) to objects in your Silverlight 3 Beta application is easy. Currently there are no meshes to define, no camera, none of that "3D engine" stuff-- just 12 properties of the PlaneProjection that you define. Granted, without a real 3D engine you probably won't be creating the next WOW in Silverlight anytime soon but you can still create some cool effects without a ton of effort.
Check out the new beta MSDN Silverlight 3D Effects Overview to get started. Yes, there are images, code, and running samples in the overview which is obviously a must when trying to explain 3D.