Joshua Thijssen has a new post to his blog today about a feature of the upcoming PHP 5.4 release, the built-in web server, and a handy way to reproduce .htaccess functionality with the help of a simple PHP script - htrouter.
The problem with the new PHP 5.4 internal web-server is that it isn't Apache. Thus it does not know anything about .htaccess. Even when you have defined your .htaccess to do authentication, the internal PHP web-server will ignore it, while in production, the authentication will be needed (if you will be running Apache, of course). Also, you need to reroute everything manually through your app_dev.php, so your URL's don't really match the way they will be on your production.
He introduces the PHP web server quickly, just showing a sample command line call to start it up and to point it at a certain PHP file as a "boostrap". With the help of his htrouter script, though, you can use "modules" similar to those in Apache. He already has the HTTP auth stuff working and more is to come.