<script language="JavaScript"> <!-- function openNewWindow(URLtoOpen, windowName, windowFeatures){newWindow=window.open(URLtoOpen,windowName,WindowFeatures);} //--> </script>and call it in the page body:
<body onload="openNewWindow('page.htm','Page Title','height=480,width=640,toolbar=no')" >
Be aware that a lot of browsers may block this popup window though...