Hi, W4life,
I would recommend reaching out directly to the Admissions Office for further clarity.
I am not positive, but I do not believe there will be periodic, regular updates on you waitlist status. If you have a specific constraint (e.g., making an acceptance decision for another school's offer), this might be worth bringing to Admissions' attention.
In the meantime, in your decisionmaking, I would err on the side of conservatively assuming you will only hear back once, with any other potential updates as a "bonus."
-Victor
WG '11