Open Source .Net Development
Web Services Security
I found a great list of interview questions from Scott Hanselmen: http://www.hanselman.com/blog/WhatAGreatNETDevelopersOughtToKnowMoreNETInterviewQuestions.aspx. I really like these because they really are not to C# or VB specific. They also are not only about web or widnows developement. IF you are going to interview with me, expect some of these questions.