Something

<?php
switch ($_GET[action]) {
     //Default to index
     default:
          include "start.php";
          break;
     //User action
     case 'user':
          if (isset($_GET['new'])) {
               include 'user/new_user.php';
          } elseif (isset($_GET['remove'])) {
               include 'user/remove_user.php';
          } elseif (isset($_GET['search'])) {
               include 'user/search_user.php';
          } elseif (isset($_GET['display'])) {
               include 'user/display_user.php';
          }
          break;
     //Upload action
     case 'upload':
          include 'upload.php';
          break;
	 //Option action
	 case 'options':
	 	  include 'configure.php';
		  break;
}
?>