Hi,
XNA isn't implemented in mono and since XNA is not directly affiliated with the development of the .NET Framework, I don't think that novell plans to support the XNA namespace. It would also be quite a huge work to replace directX by a portable 3D API like OpenGL and still achieve the same result and keep compatibility and look'n'feel of 3D app. There would also be a shader problem, Direct3D and OpenGL doesn't share the same shader language, meaning that an unix XNA project wouldn't compile in visual studio, and visual studio project wouldn't compile in MonoDevelop (or whatever IDE upon which XNA would be built).
For now, mono focuses on the core features of the .NET assambly library, meaning no entertainment feature. Mainly focused on industry needs. Not all the .NET 3.5 features are covered yet, so with the upcomming release of .NET 4, don't expect the mono team to look at XNA soon.
By the way, there is a
Mono XNA project not related to the mono projet. The mono team is aware of this project, but I don't think they'll give them any support to further develop it and the project seems discontinued for 2 years now (and seems to only cover some 2D and spriteBatch features).
