I did this fan when I installed a griffin alum radiator, I used the 3 wire fan.
heres an article that should help.
http://www.fordmuscle.com/archives/2003/02/electricfan/index.phpthe electrical is the complicated part, this thing can draw like 130 amps at startup. some have used golf cart selnoids etc. Aftrer reading a ton about this I opted for a dc controler
http://www.dccontrol.com/Works perfectly I couldnt be happier.
I got the DC controller, simple to wire up. the kit came w/ EVERYTHING, screws washers gromets, prewired harness, connectors and a fusible link as well as temp probe.
you use jumpers to set the startup temp. The fan starts slowly (variable speed switch) so no power spike. there is 1 wire that is a on/off switch for the controller. Either wire it to ignition, to a manual kill switch(water crossings) or to constant. constant allows the fan to run after you kill the engine. I used constant, works great.