Thanks jkd. That's more what I had in mind. Lemme try it out!
Edit:
Okay, that worked perfectly. For instance, Click Here. 
Code:
<script type="text/javascript"><!--
window.onload = function() {
var PopUpUrl="http://commemoratewtc.com/history/artwork/ideogram01.html"
var newWin;
if (typeof window.popped == 'undefined' || !window.popped) {
newWin = window.open(PopUpUrl,"","width=472,height=422,toolbar=no,location=0,directories=0,status=0,scrollbars=no,menubar=0,resizable=0");
newWin.popped = true;
window.location.replace('http://commemoratewtc.com/history/artwork/ideogram.php');
}
}
// -->
</script>
[edit#2]
Okay, just hit a minor glitch. If I open the popup from the page I get two popups, one of which contains the page I launch from.
Go Here and click on the image to launch the popup. You'll see what I mean.

Pretty close though. I suppose I could just target the page running in the popup, though it'll reload the existing page unnecessarily. Ideas?
[/edit#2]