financegirl,
My understanding is that pretty standard questions are covered - Why MBA, why now, why this school, goals, significant accomplishment, biggest challenge, so on and so forth. For behavioral questions, preparing an example from personal and professional front for each situation/trait will come handy. Another thing I heard is that they focus on personality, but nobody can prepare for that or develop it over a week. You either have it or you don't. Just my two cents. However, preparation is key without stepping into the realm of over-preparing or appearing rehearsed.
Hope this helps. Good luck.