Well you will be able to animate the intensity of any light put into the scene, just create a point light set it to zero intensity at the begining of the anim, set a key for the intensity then when you want to it come on, set another key at zero before the light comes on, then crank up the intensity to the level you want and set another key. repeat the opposite way for the light going off. You might want to do the same with the incandescence of the lightbulb shader? depends what sort of shader you are using for the glass of the bulb