[phantom6323]

Hello, I'm working on a project where I have 2 output devices and 2 input devices.
The 2 output devices are 2 different PC's
The 2 input devices are 2 different headsets
 
When I use my PC's sometimes I need to use different headphones for different things, and I find myself having to switch the headphones from PC to PC often. I wanted to make a box using a switch that could swap which headset is hooked up to which computer.
 
Here is an image of what I am trying to do:
 
http://i205.photobucket.com/albums/bb194/stope21/crossbox_zps1c45d1f5.png
 
I was thinking about using a 3pdt or a 4pdt type switch, but I couldn't think of how I would properly wire them for it to cross the connections properly.

 

[DingoSmuggler]

To do exactly what you want you'd need a 6PDT switch, which may be a bit hard to track down. Each source takes up 3 poles each in the centre contacts - both outputs go to each source's group of poles, but are swapped over diagonally.
To do it with a 4PDT, you'd be hooking up the grounds between 2 computers which probably isn't the best idea for retaining audio quality, but you could always give it a go.
 
You could use 2x 3PDT as long as you can get away with only one output at a time.
The 1st 3PDT to switch the sources into the 2nd used to switch outputs.

 

[Armaegis]

Simplest/cheapest solution? A pair of headphone extension cords. Then just plug 'n play as appropriate. 
 
A cheap mixer will also do the job.