I was wondering the other day if it was possible to run Sharepoint on a Linux server. Many clients run Linux based servers just to reduce their initial costs. It would prove beneficial if there was a way to run sharepoint services on linux. I have always been intrigued with the Mono project which tries to implement the .NET framework for Linux. Originally an open source community initiative it was later taken over by Novell who still continue to support its development. Currently Mono supports most command line application API's and supports most of the C# syntax. Winforms however are dependant upon Windows 32 API and it has not been possible to replicate this on Mono. However , GTK# serves a limited replacement for now. I wondered if it was indeed possible to run Sharepoint Services on top of the Mono framework. Considering that ASP.NET is partially supported over Mono, I was half expecting to see sharepoint on Mono. However it turned out to be a dead end. Quite simply because of the same reason as to why Winforms dont work on Mono. Too many calls to Win 32 API.. I have never disliked PInovke more!!
I further continued my research and realized that there are opensource alternatives to Sharepoint on Linux.
Openfire: Ignite Realtime: Downloads
Ospaces: O3Spaces - The way to extend OpenOffice.org (from sun)
Alfresco: Open Source Enterprise Content Management from Alfresco .
They certainly do not offer the features that MOSS does, but for lowend jobs, they should do the trick.