PlayStation 4's DualShock 4 controller has been recorded working with Xbox 360. The YouTuber who made it happen can be seen playing Ultimate Marvel Vs Capcom 3 using Sony's pad on Microsoft's console. Check it out here.
YouTuber RageBeefSA claims that the above video was made possible using, "a combination of JoyToKey, a Cronus Device, and Cronus Bullseye software," and follows this recent footage of DualShock 4 being used to play Hotline Miami on Mac.
It seems to be quite a versatile controller indeed. This DualShock 3 and 4 comparison video shows the device in more intimate detail.
PS4 launches November 15 in the States and from November 29 across the UK, Europe and other territories.