Web interface: single user

This probably isn't the most appropriate place to ask this, but you never know, someone here might be able to help.

I've got a pan/tilt cradle for my webcam. At the moment it's controlled by a sparkfun thumbstick, but I want to add a web interface for it. My site is apache/php/mysql, and will do most of the work so it'll only send basic commands to the arduino.

How do I limit the number of users to a specific web page? I don't mind how it's done, so limit at page or directory or part of page, but I want it done on the server rather than the arduino.

Thanks.

Apache documentation may provide an answer. It has been my experience that the apache running on my machines handles request one at a time in the sequence recieved.