Sending mail from PHP on OS X Server 10.2

I am configuring a Mac OS X Server and transitioning from several OS 9 servers on our T1. I am trying to use Open Source solutions that are based on PHP and MySQL. I just installed a rather nice list management solution called PHPList, but I am not able to send mail from it so far. I believe it wants to send mail locally. I have Apple's mail server off and all our mail continues to go through an EIMS 3.1.4 server running on Mac OS 9.1. Do I need to enable Sendmail on OS X? Do I have to make any changes to the php.ini file? Thanks for any help!