Do anyone know exactly how to go about changing the head and fog light bulbs on a 2003 Bonneville SE?

the head lights you just pop the hood open and remove light from socket and plug in new bulb without touching glass of bulb with your hands and put back in * ( i have small hands and it was hard for me), the fog lamps you have to do from underneath by removing a few body clips and then you gain acess to them.

if you are referring to the whole headlamp assembly because they are fogged over really bad as mine are do a Google for headlamp assembly i found the for 135 bucks a side for the headlamp assembly and like 40 for the fog.

hope this helped