For those who have not heard about it, Mono is a platform designed to allow porting of .Net-based applications to nearly every computing platform available (including Linux and Mac). It is open-source (sponsored by Novell) and is an essential tool for any developer who wishes to run .Net code on a non-Windows OS.
I am right now in the middle of a Desktop project being written with VS.net 2005, C# and Windows Forms technology. The powers-that-be (ie: the clients) have inquired to the feasibility of potentially porting over the code to Mac or Linux. My answer has been that if it is possible, we will have to use Mono to do it, but I cannot say anything more about its compatibility until more of the programming work is completed.
The process of porting over a completed .Net Assembly to Mono just got a bit easier. A tool called MoMA (Mono Migration Analyzer) has been released (written by Jonathan Pobst) that will do the following: given any .Net assembly (.dll or .exe file) it will go through the file and report back any potential issues that may arise using the assembly with Mono (most likely a .Net 2.0 feature that has not yet been implemented, or a calls to Win32 APIs that are not documented in the .Net API). Definitely a very helpful tool in debugging a .Net aseembly that refuses to compile in Mono.
Miguel de Icaza gives a more thorough step-by-step guide and review of his experiences using MoMA (though it doesn’t seem to be too complicated).