It says:
Ubisoft
Thanks for your interest in the Assassin's Creed Brotherhood Beta !
Due to the popularity of the Beta, this page is momentarily unavailable. Please come back in the next hours to receive your Access code.
Thanks for your patience!
Assassin's Creed Brotherhood Website
So no problem. Beta registirations are not finished it seems
edit: I just created another account for gaf. If you dont want to wait for the UBI' s website, you can start downloading the beta from the account i created if you want.