Have you got a radioshack nearby, they'd measure for free? I'm not sure if the autoparts places have DVM'* you can borrow or not. If you've got transportation it'd be worth picking up a cheap dvm.
Until then try cleaning the key as suggested. If you've got a little tube of lock de-icer then give the ignition cylinder a squirt and put the key in-n-out a bunch of tiime to try and clean those contacts inside there too. This helped when my wifes car was acting up.
I eventually just bypassed vats but to to that we need the key resistance; unless you feel like buying alot of resistors and trying the 15 possibilities.
btw - a new key is $30-50 but again, you need to know the resistance.
98 SSEi 111,222 miles.
Intense PCM, LS6 Valve springs, PEMS, FWI. Hawk Street Pads.