Put this on the parent page:
<a href="#" onclick="window.open('popupchildthing','kid','resi zable=no,scrollbars=no,width=250,height=148,toolba r=no');">click</a>
Then put this in the child:
<a href="#" onclick="window.opener.location.href='whatever';"> change parent</a>
I don't know if you want the pop up to close or not but there's a body tag Unload script i used in the parent so it shuts the child each time the page changes... nav by popup lol