i actually just looked at this last night, most of the bulbs that you would want to replace are just 194 bulbs. they slide in and out of this plastic clip that you can remove from the back of your gauges with a quarter of a turn. its pretty nice. they are like $1-2 a pair and there are 4 of them. if you dont do the whole thing, it will look funny because the bulbs are placed in the middles areas (like inbetween things) so they overlap areas.

the rest of the bulbs are smaller then the 194 but still the same concept, im not sure what those bulbs are called, im actually wondering myself