Need recommendations for eMail software

Hello all;

Not sure if it's appropriate to post this here, so if no, please accept my
apology in advance.

I've got my web server up and running (Windows NT4, Apache , PHP, MySQL and
Perl). I would like to set up and run my own mail server. I've done some
searching on google and found Xmail, Squirrel Mail, etc.

I would appreciate comments, suggestion, advice, and/or tips on doing this?

TIA.

Charles...