Showing Files On a Server

I know how to create and edit files on a server (Web site), but can you show the current files on the server? If you can how do you do it?

for PHP 5, there is scandir: http://us2.php.net/manual/en/function.scandir.php

If you dont have PHP5, look in the User Contributed Notes at the bottom of that same page for user defined functions that do the equivalent.