There was an entire How-To about this at my old board (ASOG.net). Because the gauge faces were just overlays held to the console with 2-sided tape it was simple to change thier color. After you pulled off the overlay, you sanded down the backside of the overlay until the black colored backing was gone. You then "painted" the backs of the overlay in the color you wanted.
As for the needles you simply sanded down the back of the needles until they were clear. The you painted the back of the needles in the color you wanted. The only problem was when you painted the needles in a darker color (like blue) there were not very visible during the daytime.
Lemme know if you have any questions.