We will start to map virtual domain to support IMAP.
So we just discuss about how to map virtual domain to support imap here.
if you search something like install postfix or convert postfix mailbox.
please kindly to take a look this url below :

How To Install Postfix, Cyrus-SASL and VM-pop3d
How To Convert Postfix mbox to maildir

FYI : in this tutorial i still using same configuration from How To install Postfix, Cyrus-SASL and VM-pop3d.

In this tutorial i assume you already have postfix, cyrus-sasl and courier Imap running in OpenSUSe server.

If you still don't have any mailserver running on your server.
You can follow the installation step from this URL : http://www.wowtutorial.org/tutorial/178.html

What is the different in this tutorial and above tutorial?

The different is in this tutorial we will not using vm-pop3d but we will using courier-imap

In This tutorial i will write a steps how to configure postfix to working with dspam and clamav.
So if you search my site for Postfix Cyrus SASL, Mysql, Postfixadmin, Courier Authlib and Courier Imap you can click here

So What is Dspam ?

What is Postfix, Postfixadmin, Cyrus-SASL, Courier Authlib, Courier-Imap, Squirellmail ?

Postfix is a free open source mail transfer agent (MTA), a computer program for the routing and delivery of email. It is intended as a fast, easy-to-administer, and secure alternative to the widely-used Sendmail MTA.

Postfix Admin is a web based interface to configure and manage a Postfix based email server for many users.

Here is a fastest way to fixed your dovecot if you have found any error while loading shared libraries : libsepol.so.1

If you have a centos 5.x and RHEL 5.x this error will appear when you try to running dovecot imap server.

Error shows from maillog:

[code]Jan 21 12:01:10 athena dovecot: pop3-login: pop3-login: error while loading shared libraries: libsepol.so.1: failed to map segment from shared object: Cannot allocate memory[/code]

You can fixed this by edit a dovecot.conf