[Ted S]

I love it when people take iniative! It makes everyone so much more willing to help you along.

Databases are actually pretty simple when used for a straight compare... A query for your code could read something like:

$vbulletin->input->clean_gpc('r', 'invitecode', TYPE_NOHTML);
 
 
if($vbulletin->GPC['invitecode']){
 $invitegroupid = $db->query_first_slave("
 SELECT usergroupid
 FROM " . TABLE_PREFIX . "invitecodes 
 WHERE invite = " . $db->escape_string($vbulletin->GPC['invitecode']))
 
 if($invitegroupid){
 
  $userdata->set('usergroupid', $invitegroupid);
 
 } else {
 
  // no group found, bad code!
  echo "no group found, try another code next time";
 
 }
 
}

With this code you would just need a simple table with the fields invite,usergroupid which you could create through a program like phpmyadmin. Again the sky is the limit and you may want to add more things but this should help you trudge along.

As far as adding an admin page that too is pretty straight forward. I'd suggest looking at the code in one of the more basic admin areas like Paid Memberships to see how it calls up the existing records and prints them out.