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.