On my interview days I asked that question at every single school . At every school I was told that I can call on Dec 1 to find out about my status. I interviewed really early though, back in Aug and Sept, so if you interviewed later, the decision might not be ready by Dec 1 (I'm thinking). In that case, I would imagine, they'll let you know where you stand anyway.
I know that some schools e-mail people on Dec 1 and others call. However, if you don't hear anything on Dec 1, there is no reason to worry. A friend of mine said that many people in her class did not hear on Dec 1 last year.