I don't know how to do that. But I do know one trick to accomplish that. You could set up an Apache Mod Re-write rule (which can be done in a .htaccess file). You could set it up so that anytime there is a ? in the URL, it puts .php in front of the question mark. In this model, the file on your hard drive is actually called "pagename.php" but URL calls to that page leave off the extension.