function  _phptemplate_variables($hook, $vars) {
  global $user;
  switch($hook) {
          case 'page' :
        // SUPER IMPORTANT: These rules prevent you from crashing your server :-)
        if (arg(0) != "user" && $user->uid == "0") {
            $vars['user_login_form'] = user_login($msg = '');
        }
        break;
  }
  return $vars;
}