Find yourself an 18" by 3" deep cake pan and a braising pan rack from restaurant suppy that will fit the pan. Bend the legs so that it sits half way off the bottom of the pan. Burn your charcoal(preferably in some type of basket) under the pan which is filled with water to about a half inch below the rack. Only light 2-3 coals to start and run the kettle with the vents wide open. I never check the temp. They are usually done somewhere between the 4 and 5 hour mark.
3rd place ribs at a 50 team contest a while back using this method. It is a pain toclean the pan and rack, but it makes awesome ribs every time.