It should be the same now that most consoles are using TCP/IP. Even if it is not, just some ‘massaging’ of the data would work. Here’s a quick explanation.
In most real-time multi-player games, you are constantly sending out data packets of what you are doing to a server. The server would get those packets, work on the actions you have sent, and send back the response (the client/server model). Of course, not everything is sent to the server for processing - usually client-side stuff such as sound effects and particles are just performed without server-side checking.
Likewise, your PC/console does not rely on the server to update all the time. One example is a technique call dead reckoning. You press ‘W’ or push the thumb-stick to move forward. The client tells the server, “I am moving forward!”, and at the same time, you do move forward on the client side. Before the client gets the response back from the server, it will actually start moving your avatar/tank/whatever depending on your current acceleration, velocity and bearing. It may also show you firing your weapons. However, for the purpose of whether you are hit by enemy fire or walking in a wall is handled by the server side. Which is why sometimes you got ‘rubber-banding’ - you are walking into unoccupied space, but because the server is not responding, the client deems you are walking nowhere.
So as long as the PC and console can send data to a common server, and the server can push back th responses and outcomes in a format that both PC and console can understand, it is possible for both PC and console to play the same match. If there is not centralized server, a PC client could host the game as a server.
I think Xbox360 uses TCP/IP, but the protocol is not an issue because you can usually wrap data format around another to make them compatible. Of course, the software architecture has to be designed with support PCs and consoles in the same match at the same time. As long as both games have the same action sets, same type of rules, it could work.