you have probably been to the shopping centre and seen how a key is cut. An original key is placed in one side and a blank in the other. A tracer is used to trace over the key and reproduces the image of the original key onto the blank key. This works well most of the time but using computers to cut keys is really cool.
This is a computer and a milling machine used to copy a key digitally and store the information. Then it is reproduced on to a blank key. More info at Key cutting web site