THe problem with xbox is that microsoft requires all its interfaces to be digitally signed and licensed by MS, so there aren't as many solutions for the XB.
I know the akishop pcb works, but I heard there were some issues with it, and they are sold out and in the process of waiting for v2 to come out.
I think the PCBs are a ripoff, they are like 40-50 bucks and can only handle one controller, so you would need to get 2 for a 2p pcb. I would only get one if I could not solder at all. If you want a 360 stick, just get these:
http://www.vpgames.com/p-3724-mad-catz-xbox-360-street-fighter-iv-controller-sf-4-turbo-fightpad-assorted.aspxThey are by far the BEST controllers to hack. 1) they are dirt cheap. 2) all the inputs are digital, which means simple soldering to points, no tricky analog to digital conversions needed for the trigger buttons 3) there is a switch on them that lets you trick the xbox into thinking that the dpad is the left analog stic; the controls are still digital, but it lets you control games, like limbo, that default to the left stick for movement and don't let you change controls. 4) THere is a common ground, so that means less soldering.
I had next to no soldering experience, and I hacked these, no problem.
Connecting to the PC is not a selling point, for custom pcbs. Regular controllers connect to the pc via usb, and you can download drivers for them off the MS website. So, you can get 2 of these for about 50 bucks and build a 2p cp that you can use on both your xbox and pc