ive always done it like this:
code:
<?php 
$page = htmlentities($_GET['page']) ;
 if (!isset($_GET['page'])) {
include ("home.php"); 
}
else { 
$filename = "pages/$page.php"; 
if (file_exists($filename)) {    
include("pages/$page.php"); } 
else {    
echo "Sorry, The Page Cannot Be Found";} 
} 
?>