i was wondering if it was possible to somehow emulate the signals from the 360 controller so as to control the game from signals given to the arduino. what i would do is connect the arduino to the computer, then arduino to a 360 USB port, send signals from the computer to the arduino controlling the game. i know there are devices that would allow me to do this, but if it could be done with the arduino i would rather not have to buy an extra device with only limited uses.
Really what i wish to make is something like this XFPS but i don't know if the arduino is even capable of doing such a thing.
The link you posted makes it appear that the XBox controller is a USB Host. The Arduino is not a USB Host. It is a USB slave. It can be told what to do. It can reply to requests for information. But, it can not tell other devices what to do.
There are USB Host shields available for the Arduino, that make the Arduino act as a USB Host, but, you get to write all the code to make that happen, and that is not a trivial task.
Your posts are a little bit of a contradiction. The first post you say you want a connection such as PC to Arduino to Xbox. The next post you say you want a device that lets you connect your keyboard and mouse to the Xbox.
If the 2nd is what you really want, then the Arduino is not an ideal solution. It would need to act as a USB Host and USB device. That's a pretty significant amount coding of effort. You could be better off hacking a Xbox controller. Determine all of the button and knob connections, then connect those to an Arduino. This is also a significant amount of effort.