13Jan/110
Share one monitor between 2 computers
Use source button if your monitor has 2 ports, usually both DVI and VGA ports.
DVI (White) and VGA (Blue) connections on the same LCD monitor
It was so obvious that I only discovered it as a tip in this article - Share the same Keyboard and Mouse with Multiple Computers. Doh!
Extract -
[**] If you only want to share a monitor between two computers, you don’t even need a KVM switch. Just connect one computer to the monitor using a VGA cable and the other monitor using the DVI or HDMI cable. You can then switch between computer using a button on the monitor itself.