[Al Skierkiewicz]

I can answer the electrical problem, software people are asked to chime in after that. You only want to wire one of the terminals to ground or the battery common and the "common" terminal to a digital input. When the switch is open it will be read as a "1" and when closed it will be read as a "0". Often the switches are marked NO for normally open and NC for normally closed with reference to the common terminal.