response i got from lg: "The power save option is for the display
brightness, off will always display at maximum brightness, always on
will adjust the screen at all times and night only will only adjust the
screen at night."
There is another setting in the phone for dimming/turning off the
backlight after a certain amount of time. I've also read that on some
phones (e.g. nokia) the power save setting puts the phone into "flight
mode" when it cant find a signal for a cert...