14.9. Sharing Monitors
You can share files and printers on a network, but not monitors. If you want to share your big monitor with two PCs, or perhaps your PC and your laptop, you need to physically disconnect the monitor from your PC and connect it to other computer's VGA port (see Section 1.8.1).
But if that gets to be a hassle, a simpler solution is to pick up a KVM switch (see Section 3.4), a box with a cornucopia of ports. Plug the monitor into the KVM switch's monitor port and then connect each PC's monitor cable to the box as well. To toggle your view between the two PCs, flip the KVM box's switch from one PC to the other.