PHP and Apache Authentication...

We set up a password protected directory under Apache server. Files under protected directory can only be accessed by a "WWW-Authenticate-Basic realm" dialog success. But I want to set Username and Password under php script. And only that php script can publish these protected files to the internet. Users using that cgi, don't see the Authentication dialog. Because php set the username and password for the protected directory. And serve these files to public. How can I do that? Is there any php example available?