A Replacement for Axigen MTA.

I'm looking for a replacement for the Axigen Mail Server (www.axigen.com) i use it to handle all of my mail, however i feel it is a bit too resource intensive. I've looked at Postfix/Dovecot but it is very confusing, and i'm not sure about

• How to setup multiple email domains

• Multiple Users for different domains

Does anyone know of a guide i can look at that describes in very good detail how to install an all round mail server in Fedora 11?

I am currently on a Linode 1440 plan.

Thank You.