The way Ignited (very popular amongst the civic croud) sells their kit, you can start the car either with the key or with the button.

The way I intend to do it is that only the button will start the car. You can either remove the wires from the ignition switch connector or cut them and crimp on some nice spade connectors for easy reattatchment later. Then those wires get connected to a relay, leaving the stock ignition switch with nothing to do. But I will need a key to use the starter button though....

I'll post a couple pix when the button comes in!