I know you hear this from everyone everywhere, but RELAX!
I didn't interview at VCOM, but I can tell you as someone who has interviewed elsewhere that it won't be half as bad as you imagine. In fact, it probably won't be bad at all! The object of the interview is for them to get to know you, not to scare you. For my interview, I just pretended they weren't an admissions committee but were people off the street who wanted to get to know me. Do all you can to relax - use the interview experiences listed on SDN and you should be fully prepared. Don't be like: , be like !!!