24 hour dimming system to light bulb? help needed

I am constructing an installation art work for a student exhibition and would like to know how to get a circuit hooked up to two light bulbs - making them go from full brightness to darkness over 24 hours. (this will be elapsed time as the set up will be turned off and back on again during opening hours - est 8 hours per day)

I am fairly new to all of this as you can probably tell.

thanks.

What sort of light bulbs?

normal household light bulbs (x2) not LEDs

Previously discussed possibilities:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1150063488