Microsoft released it’s long awaited Silverlight Certification (MCTS 70-506) earlier this year. It was reportedly held up several times as Silverlight transitioned from version 2->3->4. There was enough new in Silverlight 4 that the wait was worth it and now the test is out. Having been working on Silverlight projects for years, there has really been no certification test to take as a credential, though I took the WPF 70-502 test as it was the closest technology to Silverlight that was available.
Silverlight is a powerful development tool for creating engaging, interactive user experiences for Web and mobile applications. Powered by the .NET framework, Silverlight works on all major OS's plus all major browsers, including Firefox, Google Chrome, Safari, and Internet Explorer.