USPS Real time rates

<?
// ========== CHANGE THESE VALUES TO MATCH YOUR OWN ===========
 
$userName = "USERNAME"; // Your USPS Username
$orgin_zip = "90210"; // location that you are shipping from.
$add_rate = ""; // amount that you would like to add on top of usps rate, can be left blank
// =============== DON'T CHANGE BELOW THIS LINE ===============
 
// ====== Yahoo Post Script Values ========
$dest_zip = $_POST['Ship-Zip'];
$weight = $_POST['Total-Weight'];
$type = $_POST['Shipping'];
 
header("HTTP/1.0 200 OK"); //response the yahoo store needs to confirm
 
$url = "http://Production.ShippingAPIs.com/ShippingAPI.dll"; // production server and not test server.
 
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$url);
curl_setopt($ch, CURLOPT_HEADER, 1);
curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_POST, 1);
 
// This section of code is from http://www.marksanborn.net/php/calculating-usps-shipping-rates-with-php/ and is the master mind for the creation.
// You can donate at http://www.marksanborn.net/donate... Please do if this helps your store.
 
$data = "API=RateV3&XML=<RateV3Request USERID=\"$userName\"><Package ID=\"1ST\"><Service>$type</Service><ZipOrigination>$orgin_zip</ZipOrigination><ZipDestination>$dest_zip</ZipDestination><Pounds>".ceil($weight)."</Pounds><Ounces>0</Ounces><Size>REGULAR</Size><Machinable>TRUE</Machinable></Package></RateV3Request>";
 
curl_setopt($ch, CURLOPT_POSTFIELDS,$data);
$result=curl_exec ($ch);
$data = strstr($result, '<?');
$xml_parser = xml_parser_create();
xml_parse_into_struct($xml_parser, $data, $vals, $index);
xml_parser_free($xml_parser);
$params = array();
$level = array();
 
foreach ($vals as $xml_elem) {
	if ($xml_elem['type'] == 'open') {
		if (array_key_exists('attributes',$xml_elem)) {
			list($level[$xml_elem['level']],$extra) = array_values($xml_elem['attributes']);
		} else {
		$level[$xml_elem['level']] = $xml_elem['tag'];
		}
	}
	if ($xml_elem['type'] == 'complete') {
	$start_level = 1;
	$php_stmt = '$params';
	while($start_level < $xml_elem['level']) {
		$php_stmt .= '[$level['.$start_level.']]';
		$start_level++;
	}
	$php_stmt .= '[$xml_elem[\'tag\']] = $xml_elem[\'value\'];';
	eval($php_stmt);
	}
}
curl_close($ch);
$price = $params['RATEV3RESPONSE']['1ST']['1']['RATE'];
if($add_rate != ""){
 $price = $price+$add_rate;
 }
header("Shipping-Charge: $price");
?>