I just installed XMailServer on my Linux RedHat 7.3 box. It's sendmail compatible and act as smtp and pop3 server. It also supports virtual domains and it's opensource. It seems to work great and you can even manage your mail accounts from your windows desktop computer via a windows client.

I really like it so I tough I'd share it with you. Here's the URL: http://www.xmailserver.org

What's your opinion on this mail server ?