show online users and php in the header

[azmi]

i try to modify my header

i only want show the name(!) of currently "online users" in the header.
(i only found the hack with number of online users)

next problem:
i installed a chat.
then i have a mysql (php) with "how many users are in the chat"
now i want to show the number in the header.

code:
<?
include("connect.php");
?>
<?
$user = mysql_query(" SELECT * FROM wichat_users where chat_room ");
$usertoday = mysql_num_rows($user);
echo $usertoday;
?>

to show like this in the header
currently users in the chat : 6

anyone an idea?