You can use the same thing in a cookie..
PHP Code:
setcookie ('user', 'authorized', time()+36000);
then check for the cookie in the admin areas
PHP Code:
if($_COOKIE['user'] != 'authorized') {
echo 'You are not authorized for this area!';
header("Location: index.php");
exit();
}
You will need some sort of login script to set the cookie however. I'm uncertain how you were determining when to set the session.