Some general advice about the whole process
Another point, schools websites are great sources of information, they also give all the little details about the application process, so make sure you check them thoroughly. They may also have a grad student directory, including links to their websites.
The whole thing resembles some kind of lottery, so don't despair if you get a rejection from one place, you may get into another.
Depending on when you finish, have some ideas what to do if it doesn't work out (and maybe even have started on them). And if you don't make the cut this year, you can always reapply in the following years.
Get people involved, get advice and help, but in the end you have to write the letters and you have to make the decision where to go.
Give yourself enough time to do the whole thing, there will always be some unforeseen complications, and the December will be stressful.
Administrators and Admissions officials are only people, so don't worry too much if some online site doesn't change your status right at the deadline. Keep watching and after some time try to contact the departments.
In other fields a very common recommendation for applicants is to contact potential advisor. Unless you are really interested in somebody's work and want to contact him based on that, might it not be helpful in application decisions. For example at Yale every application is read by three profs and then a committee of nine makes the final decision. So you need to be very lucky to contact the right guy, and even then it can backfire. An exception might be if someone else refers you to someone (something like "Professor XY recommended that I should get in contact with you and therefore I would like to ask whether you could answer me some questions")
Campus visits might be helpful in the decision where to apply, and it should be not to hard to arrange for a visit to a lecture and a conversation with a professor, however again this will very likely not influence their admissions decision.