Quote Originally Posted by GaryMazzone
I only think I can think of to tell you is that you must believe in yourself. Don't try and just guess at the answer if you don't know tell them up front, but show them you know how to research the proper answer also.
If you follow this advice, you will do just fine.

I've had to go through a bunch of technical interviews, and I didn't know the answers to all the questions in any of them. I suspect that was done on purpose. One of the things these folks are going to want to see from you is how you handle a question you do not know the answer to.