by php I mean programatic (automated) , you will need to create a table (url) in database with columns public url , and real url ,
every public url will have real url assosicated to it ( 1 to 1 relationship) , here real url = your affilate url which you want to hide, you will show public url e.g http://yoursite.com/magic.php?public_url = 12345
when user click on this url , you will do select real_url from url where public_url = 12345 , , now store the real_url , in $real_url
return
<html>
<head>
<title>My site name</title>
<meta name="description" value="som discription">
<meta nam="keywords" value="apple,oranges">
</head>
<frameset rows="100%" border="0">
<frame noresize="noresize" src="<?php echo $real_url ?>"> // <=====
<noframes>
<body>Sorry your browser does not support frames</body>
</noframes>
</frameset>
</html>