./lib/menue_right.php erstellen
-> inhalt ist dir überlassen

./css/main.css #left und #middle ersetzen...
Code:
#left {    
    float:left;
    width:200px;
    text-align:left;
    margin:0px;
    padding:0 0 4px 0;
}
#right {
    float:right;
    width:200px;
    text-align:left;
    margin:0px;
    padding:0 0 4px 0;
}
#middle {
    float:right;
    width:780px;
    margin:0px auto;
    padding:0px;
}

./index.php div "content" ersetzen.
PHP-Code:
<div id="content">
    <div id="left">
        <?php @include_once('lib/menue_links.php');?>
    </div>
    <div id="right">
        <?php @include_once('lib/menue_rechts.php');?>
    </div>
    <div id="middle">
        <?php require ('./content' $_GET['content'] . '.php'); ?>
    </div>
</div>
achja und cool das du direkt die neue Version nimmst.