I don't think there is a programming language certification for Microsoft certs. The developer certs that are offered will allow you to test your proficiency in either Windows, Webs or Distributed Applications. Checkout www.microsoft.com/learning
Do they still provide MCAD certification?
The last time I took MCAD, it does provide me with a good deal of knowledge on C#. And if you like to go on further by learning all the stuff that goes into project lifecycle, you may continue and work toward MCSD.
Well, MCAD covers programming proficiencies of C#/VB.net using VS.net 2003. (.net framework 1.0/1.1) Now as VS.net 2005 is released and the improvements in C# and VB.net(.net framework 2.0), Microsoft have also revamped the certifications. For MCAD, it tests on 3 areas. Web App/web service developments, Windows App development and server components development. U must pass all 3 tests on these areas to get ur MCAD. U can choose to sit for the tests using C#/VB.
Now, the new credentials are Microsoft Certified Technology Specialist(MCTS) and Microsoft Certified Professional Developer(MCPD). These certification highlights ur job roles/area of expertise. The 3 areas are web app, windows app and distributed/enterprise app. Once u complete the test required for one area of expertise, u will be given the credential (Either MCTS/MCPD) for that area of expertise.
Refer to http://www.microsoft.com/learning/mcp/mcpd/default.asp for more info.