The Virtual Earth Silverlight Map Control CTP is designed to work with Silverlight 2. However, since Silverlight 3 is reverse-compatible with Silverlight 2, you can use it with Silverlight 3 Beta projects also. At MIX09 , Joe Stegman demonstrated a nice Perspective 3D demo where he rotated a DataGrid in the X, Y, and Z directions using the new PlaneProjection offered in Silverlight 3. I thought it would be fun to check it out and see how it works with the Virtual Earth Silverlight Map Control CTP . Check out the results! If you don’t have Silverlight 3 installed, you will be prompted to upgrade to Silverlight 3 Beta.