Harold,

I have replaced a few bulbs like you speak of in a GMC truck I used to have.
I am 99% sure I got the bulbs at RatShack. I also replaced some others that
have a little plastic base that snap into a holder on a PC board, you can
get the whole thing, blue condom and all, at a GM parts counter. They were
pricey, but not rediculous. If you lose or tear the plastic cover, you can
also paint the bulbs blue.

As far as using LED's to replace incandescent to replace dash backlights. I
have tried doing this a couple of times, in dashboards and in radios. The
problem with LED's is, they don't have the omnidirectional light output that
a bulb has. They generally put light out at some angle, out the front of the
device. the lighting in a dashboard is usually designed with some kind of
fiber optic plastic 'runner' that carries and distributes light to all of
the panel. So in short, bulbs just work better in this application. If you
replace them, they will probably outlast the rest of the car anyway.