[kh99]

I think what you'd do is change the query at the top of that section to be like this (parts in red added):

	$users = $db->query_read("
		SELECT user.userid, username, email, ipaddress, userfield.*
		FROM " . TABLE_PREFIX . "user AS user
                LEFT JOIN " . TABLE_PREFIX . "userfield AS userfield USING(userid)
		WHERE usergroupid = 4
		ORDER BY username
	");

then you should be able to use $user[fieldX] where X is the id of your custom field.