Access Denied Page

global $user;
if ($user->uid)
{ // this user is already logged in
print "Access Denied: You do not have access to this page.";
}
elseif (!$user->uid)
{
drupal_set_message("Access denied, please log in to continue.");
header( 'Location: /user?destination=' . substr($_SERVER['REQUEST_URI'],1) );
exit;
}
?>