pra você que trabalha com PHP, uma excelente notícia: saiu o VS.PHP 2.7 com integração a Silverlight 3:
One of the most exciting new features is Silverlight integration. With VS.Php 2.7, you can develop Silverlight applications and host them in your server side PHP application. VS.Php makes it easy to develop, debug and deploy these types of applications.
With VS.Php 2.7, you can easily debug your server side native PHP application and your client side Silverlight application within a single debugging session. Silverlight and PHP can interact using a number of standard technologies like REST, SOAP and JSON.
tá aqui o linK (dica do @zaip): Enterprise PHP: VS.Php 2.7 Released with Silverlight Integration