Belkin makes a nice 4 port switch for this. I cannot recall the model number, but the general reference to these types of hardware is KVM switch.
You will need some additional cables for the interconnect between the computers and the switch, but they can be found a most electronics stores these days.
I have 3 computers at home tied to one monitor/keyboard/mouse. You can switch between the computers via a button or keyboard command, so you do not have to have physical access to the switch.
Hehe, it aint about being cheap. I have a very expensive 21" NEC FP-1355 at home and I do not have the space for 2 more of the monsters.
