Hi, very good guide here.
I have done this a few times now on my saloon. Discs and pads all round. Luckily I have had an impact driver for over 30 years.
First time I did not have any winding tool and made a tool from cutting the end of a cheap flat multi-spanner that was lying in the bottom of a tool box. This turned it into a type of screwdriver that locked in to the slots in the caliper piston. The rear off side was a pain to wind back at first but it went with some applied effort. I have used this tool more than once with success. However, the last time I changed the pads I bought the 3/8 drive cube from Draper
http://www.amazon.co.uk/Draper-52334-8-Inch-Square-Caliper/dp/B0001K9V0E/ref=sr_1_1?s=automotive&ie=UTF8&qid=1325542634&sr=1-1
This tool did not fit until I cut two pins off the side with four pins. It then worked perfectly with the 3/8 ratchet attached.
My son has an Audi A3 (2004) 2.0TDi. He was home from the forces when he needed to change his rear pads. He bought a wind back tool and this made the job much easier, I will be buying my own.
The Audi pads were down to the metal on one side and we stripped this off first only to find GSF in Lincoln had given him the wrong replacement pads. When I saw his old pads I recognised these were identical to those on my Accord. I had some part worn pads in the garage that we put in while he went back to GSF and exchange for the correct pads. I wonder how many cars use these pads?