Playstation VR will allow you to use any non-VR content on the PS4 via their new headset; on a virtual giant screen in what Sony have called cinematic mode. But, as it has now been confirmed this will also work on other systems as well.
This was first reported on Reddit, and then later verified by Gamespot, that the cinematic mode also works with PC and the Xbox One. The reason for this being that the headset uses an external processor unit, which basically servers as a HDMI splitter to allow the PS4 to output to both your headset and the TV simultaneously. Meaning all you need to do is plug something else into it in place of the PS4. Gamespot have reported;
“In place of a PS4, you can plug in something else–like a PC–and have that device output video to the headset. We tried it out quickly and were presented with our computer desktop on a big screen. An Xbox One also worked successfully. How much use this will actually be remains to be seen. We couldn’t find a way to re-center the camera, which would normally be done using a controller PS4. As the PS4 isn’t actually a part of using Cinematic mode like this, that isn’t an option.”