the light you are seeing is simply from the backlight of the lcd. the apple logo is translucent, and that's why it illuminates. that said, there is no easy way to change its color. however, i do have a good friend who took the back plate off of the display on his ibook and put some stage light filters in there to color it like the original rainbow apple. but that was quite a tricky mod. basically, there's no real way to do it without tearing the computer apart.