Codice PHP:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
<title>Titolo Documento</title>
</head>
<frameset cols="*,*" frameborder="0" border="0" framespacing="0">
<frame src="file_frame_left.htm" name="leftFrame" id="leftFrame" title="leftFrame" />
<frame src="file_main.htm" name="mainFrame" id="mainFrame" title="mainFrame" />
</frameset>
<noframes>
<body>
</body>
</noframes>
</html>
in linea di massima è così, prova... (non l'ho ne validata ne provata)
dovrai fare dei tentativi
ciaux