How easy or hard is it to implement a Push button ignition start?

It's not hard i wired up a push button start for my ED falcon.I did it the cheaters way.I just disonnected the starter relay and then wired up another relay for my push button switch.Is easy to config up and easy to go back to normal.
I bought a black style switch and fitted it in where my cigarette lighter used to be.

If you want to set it up like they do in the BA GT's im sure there is a doco on here about it.Do a search...