I would love to see a howto on setting up PostPath collaboration server and linking it with an Active Directory Server. PostPath can be downloaded for free for up to 12 Users from: http://www.postpath.com/downloads And an 180 trial of Windows Server 2003 can be obtained from: http://www.microsoft.com/windowsserver2003/evaluation/trial/default.mspx I hope that mentioning windows here isn't illegal but without a fully fledged replacement that I can play with, unfortunately my work aren't going to go anywhere else, at least if I can prove that PostPath is a viable alternative to Exchange then I might make some headway away from Windows. Thanks
Just for the record I'm not 100% set on Post-Path any decent exchange type collaboration server would do. All I need is shared calenders and an IMAP account really. Open-Xchange looks quite good as well, but I would take it on advisement.