The department fax number is 718-997-3513.
There is a sign-up sheet on my door for office hour appointments. Be sure to sign up a day in advance so I will know you are coming. Appointment times are Tuesday and Friday from 12:00 to 1:00 and Tuesday evening from 8:15 to 9:15.
The best way to reach me is by e-mail, which I read regularly.
I prefer that you use the address vickery at qcunix1.acc.qc.edu for everything concerning CS-200, including both questions and homework submissions.
See the Using Unix page on Using E-Mail for information on using e-mail.