PC games aren't built to be played like a console game. Your thinking something like two players playing a match on a kinda split screen kinda thing. PC games don't do that. I know you can use an 360 controler as a PC gamepad, but to use two at once. Even if you had dual monitors but one PC, you cant boot the same instance of one game twice like that. Invest in a 2nd PC and lan, that's your only choice.
There ARE many PC games that two people can play at once - in particular sports games (I've played 1 vs 1 and 2vsCPU games of FIFA and ProEvo), so I think his question is perfectly valid.
Unfortunately, I can't answer the OPs post for certain. I HAVE used two controllers simultaneously on a PC, but they were both Logitech Dual Action controllers. However, I can see no reason why the Xbox 360 controllers should be any different. When you plug the second one in, Windows will assign it a controller number, and your game should be able to recognise the two controllers as being different, even though they are the same model.
You are about to answer a thread that has been inactive for more than 6 months. If you still wish to proceed, please ensure that your posting is original and does not duplicate or overlap any prior responses to this thread.