Sendmail, I've had enough of it!

ARGH!!! I'm seriously sick of this! I've spent days on end reading documentation, trying settings, seeking help, and it still won't bloody work! So I've taken the ultimate step, and applied the trusty rm -rf command to everything that has to do with sendmail! In other words, sendmail is no longer on my systems. Screw it, causes more bad than good! Ok, now surprisingly enough I do have a final question regarding PHP/Mail (And I mean final!) How can I get PHP to send mail through a local SMTP server? I'm running Linux RedHat 7.1, latest Apache and PHP. I have eXtremail installed locally. It's a POP3/SMTP server. Works fine - fact. There's 3 configuration options in php.ini that I've been playing with, no matter what the combination is, I don't really see it doing anything different. I've read everything relevant on php.net and still can't find anything. I'm sorry if this is a really stupid question. Thanks soooo much for all your help! Liam