URL- . PHP 5 - urlencode(), http_build_query() - . , / GET , , .
<?php
$base_url = "http://www.mysite.com/plistReader.php";
$data = Array("id" => 123, "dangerous" => ":?&= are some sensitive chars");
$itms_url = "itms-services://?action=download-manifest&url=" . urlencode($base_url . "?" . http_build_query($data));
header('Location: ' . $itms_url);
?>