This is a rather extensive article describing the configuration of a high performance Mail server for Small and Medium businesses, with a focus on security, mail retention and accessibility though IMAP and webmail.
This setup will work on most -if not all- linux distributions without major change and the instructions should work out-of-the-box on all recent RedHat derived systems: RedHat Linux, CentOS and Fedora.
You can view the article as a single long page or as a series of smaller articles describing each steps to perform :
I hope you will find these helpfull. Let me know if they helped or if you have any comments: or just leave your comments in the comment boxes at the bottom of each article.
You will find relevant resources in each article above. The following resources are more wide-ranging and are excellent articles to use as references.