If you have passed exam 70-536 then you have to decide to take one other exam to get MCTS. Check the thread below for VS2008 exams and the link below for VS2005 MCTS exams. That exam depends on the platform you are using for development, Winform, Asp.net, WCF, WPF and ADO.NET.
http://social.msdn.microsoft.com/forums/en-US/csharpgeneral/thread/0309997e-49f2-4425-9172-a58dc41fff19
http://vakul.wordpress.com/2008/04/28/visual-studio-2005-certification-series-mcts-and-mcpd/
Asp.net MVP, MCPD Web C#, MCTS TFS, MCITP BI and DBA