I had a phone screening by HR and then 3 phone interviews. Two were technical and one, more about consulting. In the technical interviews, I was asked a lot of questions about almost every aspect of C#, the .NET framework and ASP.NET. It was very intimidating, the interviewers had a set of about 400 questions! But overall, it's very general questions just to make sure you're well versed in the framework. It IS fine to say you don't know something; they expect that. Don't try to make things up, that would be useless.