Um. Me and my friend are both doing it because we WANT to do it. Since we both want to do it, we would like to do it together, thats all there is to it. I'm sure there's various horror stories about couples breaking up and friends fighting but I've also heard stories of people who did it together who had awesome experiences. I'll take my chances. It's more likely that I won't get along with a stranger as a roommate than my best friend of 6 years...
Anyway, I wasn't aware that you could "sign up" to be with a specific room mate or anything about a room mate matching service. Could you elaborate?
Also, before I choose my date, it says that if you're planning on coming down with another CP participant, you should accept within minutes of each other so you can choose from the same dates. Are there any people out there who ever got accepted really late? What dates were available to you? I'm guessing Feb. 3 isn't a popular one.
Like I said, the desire to do it regardless will ensure a good program. I can almost assure you of that. (They'll go over some of the horror stories during your check-in day.

) As far as the stranger thing goes some of the people I enjoyed spending time with the most on my CP were people I'd never met before in my life, including Andrea, my roommate from Brazil who barely spoke English.
You'll need your application number, and your friends. You'll then need to login to the same system you used to accept your application. From there you'll just proceed to the roommate matching system, and type his number in. When he's accepted, he'll have to do the same, otherwise it won't go through.
If you're not able to do it before the deadline, but can get the same date, just stand in line next to one another and they'll stick you all in the same house--that's how I got my roommates. If there's anybody else you meet there, or online, that you want to room with, you can do roommate matching with them too, or the line thing.
The dates are standard across the board--or at least they were when I did the program--so everyone should have the same dates unless one gets filled. (I guess the reason for suggesting accepting at the same time.) Earlier dates will fill up because people want first dibs on housing. So, yes, Feb might be a better deal.