USPS shipping calculator

Hi David,
Is it possible to add a php shipping calculator with this script?

<?php
....
....
$usps->setServer("http://production.shippingapis.com/ShippingAPI.dll");
$usps->setUserName("xxxxxxxxxxxxxxxxx");
$usps->setService("ONLINE");
$usps->setDestZip($tozip );
$usps->setOrigZip($fromzip);
$usps->setWeight(10, 5);
.....
.....
.....
?>
It would be nice to have this feature available for customers
Thank you
zelda