I’ve watched the Mono project with great interest as they are the group furthest along in an open source version of the .NET platform. If you’ve ever wondered what a .NET application would look like on Linux or MacOS, then Mono should satisfy that curiosity. What makes this most current version so worthwhile is the inclusion of all the recent additions to the .NET framework. By default, the mono compiler can compile code written for the .NET 3.5 Framework (just released in November!), including such new features as LINQ and Silverlight. Virtually all of the .NET 3.0 foundation components are included as well, including those for web and presentation development. The project includes some fairly robust examples and documentation and an IDE called Monodevelop for more sophisticated development. And of course, if you don’t like a certain implementation in Mono, because it is open source, you are free to make a change to the source code and submit it.
The Mono 1.9 SDK is freely available and can run on MacOS, Linux, and (amusingly) Windows operating systems. For web applications, plugins for different web servers exist, although Apache’s is the furthest along and the built-in test server is very good for non-deployment purposes. Overall, this is a very good release over the previous and serves to whet the appetite for the much anticipated Mono 2.0.