Two Computers One Monitor switch

Using one monitor on two computers?
i am going to buy a mac mini. I currently have a Gateway and a 21inch LCD screen. Is there a way i am use them both on the same monitor and plug them into a little box/device and just it a button and switch over? If there is how much are they and what will they cost me?
can i use the same keyboard and mouse or will i need two of each?
Yes there is a device, its called a KVM switch, where you can use one monitor one keyboard and one mouse for two computers, I think the smallest KVM switch has 4ports, so you can actually use 4 computers on 1 monitor mouse and keyboard
English, the key to the world
Of the many languages spoken in this world, English is the most popular. It is an international language which opens the door to the entire world. It has become the key instrument of globalisation, today.