Using real name instead of username at registration

[emucu]

Hello,

I was wondering if there is a way to force users to register with their real names instead of nicknames? I think it's not that hard but was just wondering if there is any hack for that

Plus, how can i make an automated system (maybe using preg match at default vb settings?) so people will have to use Name Surname for registering, so it should contain 2 words with a space. Can i set it up using preg_match, if yes, then how can i do it ?