That works, but careful on upgrades if this file is part of update script.
I have also achieved it by creating a block and applying to home layout page per your first comment and it works the same as the second option I posted. Its just a more permanent effect if an upgrade were to happen like you said. His response to your first post was that it seemed too difficult (IMO easier than the options I gave).
Paul, if you want to have a more permanent option do the following:
1. Log into the admin side of the cart, browse to Design -> Blocks
2. Click on the "Insert" icon to the right of the page
3. Give your popup a name and title
4. Add the following code to the custom block content (make sure you click "Source" to enter the code side of the editor)
<script>
$(document).ready(function(){
testwindow = window.open("URL HERE", "mywindow", "location=1,status=1,scrollbars=1,width=500,height=500");
testwindow.moveTo(0, 0);
});
</script> 5. Click Save, then browse to Design -> Layouts
6. On the left, click Home Page
7. At the top, find a slot that has "--- None ---" and click the drop down. Find "html_block:: YOUR POPUP NAME"
8. Click Save.
9. Try it out