mordred is correct there, but.... if you were tracking on an intranet you could get the location of the child window by polling it.
Try this, it was a proof of concept. Note that it will only show URLS that are on the same server. It updates every second, and has a counter in it, the thought was to time how long the user was at a particular page. It never got off the ground as we convinced them it was not a good idea to spy so blatantly
<form name=temp method="post" action="http://www.xmission.com/~tnelson/mirror.php" onSubmit="return validateForm(this)">
<input type="text" name="URL" size="50" value=""><br>
myCount = 0;
document.temp.URL.value = myCount + "URL: " + Swin.location;