XNA to MOGRE
Does anyone know how to integrate XNA into MOGRE?
What do you mean by integrate XNA into mogre ?
You can use some parts of XNA with mogre.
For example input system or sound system.
Well, you can use C# with Mogre and XNA. And I want to use XNA with Mogre.
Sorry, if you want to use XNA for rendering with Mogre that is not possible. Mogre is just a wrapper for Ogre which uses its own C++ renderer and XNA provides access to the graphics hardware from C#. If you want to use XNA (maybe to write a game for XBox) then you should take a look at Axiom which is a native port of Ogre to C# and has a XNA renderer.
If you want to use Mogre you are currently stuck to the Windows platform, because Mogre uses C++/CLI which is only supported on Windows. And being stuck to Windows means there are better choices than XNA, like using SlimDX to access DirectX. XNA is a very nice platform that I use myself in another project, but it has some drawbacks that I don't really like to live with if there are better alternatives. For example there are some very annoying restrictions in the sound library that don't even allow an easy way to access the sound buffer to implement things like streaming. I don't even know if there is any way at all to access these buffers from XNA.
On the other side, if you want to support only Gamepad, Mouse and Keyboard as input devices, XNA is a really nice way to access these devices in a very easy way.
But I don't want XNA as a renderer
XNA are just some libraries so you can use them.
Personally I'm using XNA input in my mogre project.
This is C# question more than a Mogre question.
Just reference some *.dll from XNA directory into your solution.
And I can still make a Xbox game?
No you can't.
If you want to make a XBox game with XNA you can only use native C# (.NET) components. Because Ogre is a C++ engine you can't use it. Like I said before, you should take a look at Axiom, a C# port of Ogre with a XNA renderer.
Mogre you can use by C#, but it's just a wrapper (translation layer) for the Ogre engine, which is written in C++.
On the Xbox you can't use C++ libraries, not even a wrapper.
Possilbe alternative for the Xbox you find in the first post of the thread Deciding on MOgre