User real name question

[محروم.كوم]

Hi all*

I am currently running a cg artworks related forum (http://www.cgfeedback.com)* and I added an extra profile field to get people to put their real names.
I am also moderating new users but their profile details are viewable in the forum even while waiting for registration approval.
The thing is I am getting more and more accounts that are using the real name field to put website url (spammers).
I know there is a way to put some regular expression to force the data to match a specific format but I have no clue how to write those PCRE.
Is there an easy way to forbid any name to start with http:// ?

Thanks for your help*

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