I had the same problem. A Halti worked for a while, which attaches around the neck and snout, and the lead is connected to the snout so that when the dog pulls, it's head gets turned to the side.
This stopped working after a while for me though, not sure why, but it just stopped being so effective.
I know a guy who trained his Pointer with a Halti by having the lead on as normal so that the dog got used to the lead being lose, but also controlled the dog with a halti on a very thin lead, and stopped him from pulling like this, and apprently that worked very well.
With my BC cross Bramble, I also tried making her sit whenever she pulled, but this went on for a week or so and had little or no effect on her.
Currently I walk her on a flexi lead, and have found that to be the most successful - I know it's the lazy way out, but it gives her the freedom to walk slightly ahead as she wishes, (she has road sense and automatically stops and sits at pavements) and most of the time doesn't reach the end of the lead, I've found that often she'll look back to see where I am and even stop and wait for me.
These are some of the examples that I've tried, and although it doesn't provide a permenant solution, or teach the dog to heel correctly, it does provide my arm with some relief!
If you do a search on this on the General board, I'm sure you can find other topics on the matter. Good luck!
