I recently was asked to find an email solution that was easy to use, easy to install, and open source or Free. I used qmailrocks in the past which was not easy to install! I started to look around and I really did not find much that was EASY. I decided to take a look at Zimbra. I had a couple friends a few months ago mention it to me and even ask questions about it. So I decided to install CentOS 5 and Zimbra. It was really easy all you have to do is get the server setup with the requirements then run the install script. I got it up and started testing it. It seemed to work great. After doing a little more research I found out you could easily use it as an Exchange replacement. It has an easy to use interface for both the Admin and User side. You can use an normal email client to check your email. Zimbra seems to be one of the easiest email solutions I could find out there that is FREE!