I’m all signed up for the 70-340 beta exam (numbered 71-340 in beta), Implementing Security for Applications with Microsoft Visual C# .NET. I take it Friday, April 23. This should be quite the challenge. The only references listed are to Writing Secure Code, 2nd ed. and the Improving Web Application Security: Threats and Countermeasures patterns and practices guide.
One good resource I have found is Jason Row’s 70-330 Study Guide. Although it is VB-centric, it’s all applicable to C# (with maybe minor code syntax changes).