well....you can do it for free if you want to. you just need to cut the power supply to the foglight switch and jack into another power supply. make sure its one that is only getting power when the is running. luckily i have a vert so i tapped into the power of the drop top motor but my buddy did it by tapping into something else....
ok, nevermind....here you go
http://www.mustangworld.com/ourpics/fcar/fog1.htm
i just saved some of you some money and it looks pimp too when its just about dusk