This is not a php question...try posting in the [urlhttp://phpbuilder.com/board/forumdisplay.php?f=27]clientside[/url] forum?
here's a tip just the same. you should probably write a javascript function in your page that opens two windows, then call that function from the onClick of the <a> tag.
<script language="Javascript">
function openTwoWindows() {
window.open('waiting.php?email=$email&banner_id=$row[banner_id]&action=open','loading','toolbar=no,left=50,top=50,scrollbars=no,resizable=no,width=400,height=100,alwaysRaised=yes')
window.open('<?=$row['link_url'] ?>','link_url','toolbar=no,left=50,top=50,scrollbars=no,resizable=no,width=400,height=100,alwaysRaised=yes')
}
</script>
or something like that.