Cocos2D-XNA is a 2D/3D game developer’s framework that is written specifically for XNA. XNA is the game API developed by Microsoft for independently published games on Xbox Live Arcade.
To support other platforms than the now deprecated Microsoft XNA targets, Cocos2D-XNA supports the MonoGame runtime.
There are Visual Studio extensions available from the online gallery. From Visual Studio, choose Tools -> Extensions. From the Extensions Gallery enter cocos2d in the search box and start your search.
Install all of the extensions that you are interested in targeting. Each of these will create an empty, and runnable, game project that you can modify.
After you have installed the extensions, return to Visual Studio. From the File menu, choose New Project and find the Cocos2D project type node.
Read KJPOU1′s Getting Started Guide on Cocoa-Mono
This project is open source, freely available, and free of royalties or encumbrance.
Cocos2D-XNA software is released under the highly permissive MIT License.
The source code is hosted at github: https://github.com/Cocos2DXNA/cocos2d-xna
For more details see http://www.cocos2dxna.com/
What about the license? Is there a fee?
Its open source so its FREE