The easiest thing to do is to train him to lead better.
Like Peppy said , get a rope halter, first.
when you go forward, and he pulls back, you stay facing forward in the leading position, then you take the long tail of the leadline (did I say to get a long leadline?) and swing it around behind you so that it snakes out toward his body. The further back you can reach, the better. He will be surprised and will move. Maybe not forward, maybe sideways. IF he moves backward, do it again until he moves in such a way that some slack is put into the line. When that happens, stop tossing the rope. Do not pull in the slack rope when the horse creates some by moving his feet. Just start walking forward as soon as the horse's feet are unstuck and he no longer is pulling backward. He can move anywhere he wants when you pull on the rope and swing the tail around behind to unstick his feet, (as long as it's not backward). Eventually, you will put forward pull on the rope, he will resist, you will raise your other hand with the tail of the leadline, and he'll come forward BEFORE you even have to shush him along with it.
Last edited by tinyliny; 12-16-2012 at 07:22 PM.