Car won't start - bad ignition switch?

I jumped in my 71 /6 Scamp this morning to get to work and was greeted with what I thought was a dead battery. Turned the ignition and all I got was the oil pressure idiot light, no cranking at all. Weird. I cleaned the terminals and boosted the battery - same result.

What are the common symptoms of a bad ignition switch? I've noticed that I can occasionally take the key out of the ignition and the door buzzer will come on when I open the door. I jiggle the switch and the buzzer stops. It happens maybe 5% of time.

Assuming the battery voltage and connections all check out when I go over it this weekend, what's my next troubleshooting step? I drove it home last night, no problems. It's my everyday car, so I'd like to get it going ASAP.

Thanks, guys.

-John