To 4star-admiral: I got ur msg and have replied to you!! Here are some more information. The interview is pretty laid-back but at least you need to have fluent oral english skill and can give your thoughts clearly. I do believe the fluency can be practiced. My interview went very very well among my 6 B-school interviews and our talk lasted around 1.5 hours.
But i think generally the interview won't last more than 45 mins!! be prepared and be confident no matter what kind of questions u are asked!! that's my 2 cents and wish you very good luck!!