To change the color you first must remove the left side of your dash with the, I beleive five screws on the dash itself, you can search for tacoma dash removal and probably get some good instructions. Then you will need to remove the cluster-- four more screws, it is all one big piece. This will give you access to the back. Easy from there, just pop out the old ones by unscrewing the four holders, and pop in the new colored bulbs 194 to all four slots.
This process becomes easy, as i have changed the color a couple of times... i am now at hyper white, which turns out kind of nice.
http://superlumination.com/
get any bulb you want here... i prefer the LED... less power, more light