Yes you can use the Xbox controller for Halo PC. on Ebay, if you search for a USB adaptor for an XBox controller, there are many made by this japanese company. However, you will find out you will run into problems while playing with the controller. First, there is no auto targeting. It might not seem like a big deal but it does make the difference. Second, controling Halo PC is much different from the Xbox version, so there may be some compatibility issues as well as having a tough time handling your pistol. Either way, sniping is much easier with the mouse so you shouldnt really bother.