Question re: PHP, Qmail and incoming email

Hi I'm new to this group, and new to PHP so excuse me if I make any faux pas. I've looked throught the archive to my problem with no joy. I think my question is quite a simple one, if you know the answer. I want to produce a php script to process incoming emails to add a "ticket" number to them and to check if they already have a ticket number on them. My ISP uses: Unix, PHP3/4,Apache, Qmail. I've worked out how to pipe emails from a certain address to a script, but I don't know how to get the script to handle the email once it arrives. Does the email, that is piped, appear as a predefined variable of some kind... any tips, advice or pointers toward documentation that a newbie could understand would be enormously helpful TIA Allan Goacher Cybercandy Ltd www.cybercandy.co.uk