Need help in starting PAM programming in PHP

Hello Team, I have an application written in PHP and running on Apache 2.2 and Red Hat environment. We have security being verified from database. I want to use PAM in my code. Can you please address the following questions or provide me a guide which shows step by step conguration needed for setting PAM in the code :: *How do I start using PAM? How do i use bool pam_auth() function in my code ? What all configurations I need to do on my RedHat or Apache 2.2 server? I couldnt get much on google nor on pecl website.* Please help. Thanks!! -- Regards, Vishnu G Singhal If You want to walk fast ..walk alone ,but if you want to walk far walk together - Ratan Tata