Htcs,
Hey dude, Here is a guide to setting up a server (which can be used for mail) in FC5 even though it says 64bit it won't make a difference in setting it up, with Screenshots and all
http://www.howtoforge.com/perfect_setup_fedora_core_5
and here is how to set a server up in Ubuntu 5.10 (If you want a copy I'll mail you one)
http://howtoforge.com/perfect_setup_ubuntu_5.10
hope this Helps,
Jake