I believe you can follow the instructions here to apply for housing http://www.umbc.edu/reslife/apply/freshmen.html
You can request specific roommates by adding roommates to a group after you get their roommate code. I am 99% confident I am going to UMBC because of the scholarship money and honors program, but I am still waiting to hear from Hopkins and Carnegie Mellon. I got my Virginia Tech admission in the mail two days ago by the way.