I was on the waitlist last year. I would definitely recommend sending in a LOI if you haven't already. I would also start calling the school next week to see if you can get your rank. If you're as anxious as I was last year, you can call the admissions office on a near daily basis to see if the list has moved. It might be best just to call once a week to retain some basic level of sanity. The list moved very slowly in May last year, so don't get too discouraged if you aren't moving immediately. You should always feel free to call or e-mail Mike Istwan. He might not be able to give you a great idea of where you stand in the early part of the summer, but as July approaches, he should be able to give you a fairly good idea of what your chances are. He was a great help to me last year and he never showed any visible signs of annoyance at my continual pestering of him.