[kh99]

Well, you could do this:

if ($result = $vbulletin->db->query_first("SELECT COUNT(*) AS count FROM " . TABLE_PREFIX . "user WHERE usergroupid = 12"))
{
      $num_members = $result['count'];
}

Then either pre-register $num_members to a template where you want to use it, or else create a php type block and return some html that includes that variable.