Running php scripts on a hosting server for clients

I would like to know what is the best way to set up a server so that I can let my clients run a php script from there web sit that I have set up to run anywhere on the server. Like you would with perl programs. I have set up a directory on my home web directory called php-sys and set Alias /php-sys/ /home/sites/home/web/php-sys/ in the httpd.conf file. I want to set up a web based file editor and directory program that they can call with http:\\theredomain.com/php-sys/editor.php. When they call this program it needs to just list the files in there directory. I can get this program to run now but it shows them the files in my home directory. How would I set this program up to work the way that I want it to. What I really need to know is what would be the processes to do this with any php program like form mailers counters etc. I would rather use php programs instead of cgi programs to offer to my clients. NorthWestHost Your web host provider www.northwesthost.com