If I understand what you are after then frames are not neccessary - unless, like me, you need them on the page for other reasons.
One of the beauties of php is how easy it is to generate web pages from code fragments. Simply write the html to display the AD, save it as a seperate file, and then include that file in every page wherever you want it to be displayed.
// for the add at the top of this page
<?php // ads.php
?>
<!-- OAS AD '468x60-1' begin ------>
<SCRIPT LANGUAGE=JavaScript>
<!--
OAS_AD('468x60-1');
//-->
</SCRIPT>
<NOSCRIPT>
<A HREF="http://63.236.18.118/RealMedia/ads/click_nx.ads/intm/linux/www.phpbuilder.com/board/newreply.php/index@468x60-1,468x60-2,125x125-1,sitetext-1,cp1,cp2,cp3,cp4,cp5,cp6,cp7,cp8,cp9,cp10,cp11,cp12,cp13,flex,house_ribbon,ciu!468x60-1">
<IMG SRC="http://63.236.18.118/RealMedia/ads/adstream_nx.ads/intm/linux/www.phpbuilder.com/board/newreply.php/index@468x60-1,468x60-2,125x125-1,sitetext-1,cp1,cp2,cp3,cp4,cp5,cp6,cp7,cp8,cp9,cp10,cp11,cp12,cp13,flex,house_ribbon,ciu!468x60-1" border=0>
</A>
</NOSCRIPT>
<!------ OAS AD '468x60-1' end ------>
// then in each page
<body><center>
<?
include_once 'ads.php';
?>