[kh99]

If you create a profile field that's on the registration page, say it's field7, then you can edit the newuser phrase (the ones of type 'email body'), and add something like:

Phrase: {$vbulletin->GPC['options']['field7']}

Edit: well, that will work but you might need a plugin to 'clean' that value. Although offhand I can't think of anything a user could enter that would cause problems.