im Headbereich wie folgt:

<?
    if (isset($_GET["page"]))
    $page = $_GET["page"];
    else
    $page = "home";
?>

im HTML Template (im contentbereich) dann:

<?
 switch ($page)
 {
     case "home" : include "home.php"; break;
     case "news" : include "news.php"; break;
     case "contact" : include "contact.php"; break;
     case "impressum" : include "impressum.php"; break;
     case "guestbook" : include "guestbook.php"; break;
     default : include "home.php";
 }
 ?>


aufgerufen werden die Seiten dann via: /index.php?page=contact