define ('FRONTEND_LOGIN',    'my_login'); // тут задай свой логин
  define ('FRONTEND_PASSWORD', 'my_password'); // тут задай свой пароль

  if ($_SERVER['PHP_AUTH_USER']!=FRONTEND_LOGIN
        OR $_SERVER['PHP_AUTH_PW']!=FRONTEND_PASSWORD) {
    @header("WWW-Authenticate: Basic realm=\"Only for members!\"");
    @header("HTTP/1.0 401 Unauthorized");
    echo "Only for members!n";
    exit;
  }