As far as colors go, honda uses a clear white bulb. The actual color comes from a "filter", or lens against the guage. You could remove it, and place in your own colored bulbs, or even LED's. Some company's online offer them. Try a Google search for dash bulbs.
There are two phillips head screws under the guage hood. Once you remove the screws, it's best to tilt your steering wheel down as far as it will go. Pry the guage surround starting from the top, down both sides. The surround is fit in tight, so it will take some force to remove it. Just go slow, and dont force it too hard, it'll come out. Also try to wiggle it free. Once the surround is out, there are ( I belive 4) some screws holding the gauge assy. in place. Once the guage is free, you'll notice the two connectors on the top, in the back of the guage. They are colored to match the connectors, so don't worry about mixing them up. With the connectors disconnected, you can now remove the entire guage assy.. The bulbs are pretty easy to find, they are in turn sockets. Either green, or blue, sometimes even grey, white, red, or even orange... Turn the socket counterclockwise. Not too much, maby a 1/4 turn, then the bulb is free. The bulb is part of the socket, although it can be removed, it's not suggested. ( And it's friggin' hard to remove )