It really depends on the school, and how you applied. I assume the check they cashed was the application fee, and that this is just for spring semester start?
Some schools render a decision in a month (very, very few though) and others can take anywhere from 3-4 months. If you applied early decision, you'll get a decision much faster. If not, it just depends on how many applications they've received, when the deadline to submit one is, etc. Just hang in there, and don't worry about it, because it's going to take awhile.
Oh, and the college usually sends notice that they've received your application and are rendering a decision on it, and once that decision is made, they will send notification (either by mail or email, again, depends on school) with acceptance or denial.
