Mine

        header("Content-Type: application/force-download", false);
        header("Content-Type: application/octet-stream", false);
        header("Content-Type: application/download", false);
        header("Content-Transfer-Encoding: binary");
        header("Content-type : ". $type, false);
        header("Cache-control: private");
header("Content-length: " . $length);

        // get the browser name
        $browser = $_SERVER['HTTP_USER_AGENT'];

        // echo "setting header Content-Disposition: attachment; filename=".$file."\n\n";
        // due to a bug in IE6 we can't use this -
        if (preg_match('/MSIE 5.5/', $browser) || preg_match('/MSIE 6.0/', $browser)) {
            header('Content-Disposition: filename="'.$filename.'"');
        } else {
            header('Content-Disposition: attachment; filename="'.$filename.'"');
        }