XML : Keeping html tags in PHP post

I have code that sends via PHP POST a FedEx tracking link in an xml file. when it goes the tags for the link are broken down into characters like below. What are I doing wrong?

Here is my code:

  $tracking_url = '<a href="http://www.fedex.com/apps/fedextrack/?tracknumbers=' .       $_POST['tracking'] . '" target="_blank">' . $_POST['tracking'] . '</a>';      $_POST['skuMessage3'] = $_POST['skuMessage2']. ' ' . $tracking_url;    

And here is what they get on the other end.

  <a href="http://www.fedex.com/apps/fedextrack/?tracknumbers=782663509917" target="_blank">782663509917</a&gt    

and here is what I want.

  <a href="http://www.fedex.com/apps/fedextrack/?tracknumbers=782663509917" target="_blank">782663509917</a>    

Any help would be appreciated.