When I plug my moto droid into a charger a bright white light comes from the micro usb port. It is super bright when its on my nightstand and the lights are out. It drives me nuts.
Simple hack: cover it with a small strip of black sticker. Or, cover the nightstand with a handkerchief.
Complex hack: Find if the USB port driver allows you to turn the light off; I think that's quite unlikely, as it may be hardwired to the hardware itself.