All you really need for a Facebook account is an E-mail address.
You can use real information or a pseudonym when you fill out the profile information. I've had several over the years, and it doesn't really matter what you put in the remainder of the profile as long as you use a valid e-mail address. At a minimum, I'd recommend using a Birthday that puts you over the age of 18 (or your real birthday) and select geographic information that is close to where you live. Beyond that, you could use any name you like, gender, etc.
Just make it up and have fun with it.
Worst case is that Facebook _could_ terminate the account if they ever figured out Jonny Fizzbucket (for example) wasn't really your name, since the associated e-mail is what keys the account, you could then simply create another e-mail address and re-register with "Bob DePhillistine" if you liked.
S.