New Member Registration Page Question

[bazookajoe]

My forum is a motorcycle related forum and I often have new members register using their business name as their screen name. After registering, these newbies often start posting links to their site, contact info etc. I would like to add a note somewhere on the Registration Page so that they know before choosing a screen name that business names are not allowed unless they are an approved sponsor. Anyone know where or how to do this?

Thanks!