Hi,
My dog used to pull a lot and choke herself, even with a regular cloth collar.
We bought her one of those collars that people have been describing that go around their face. It is called a "gentle leader" it puts pressure right behind their ears when they pull. It did stop my dog from pulling but she got really depressed when we brought it out and i think it took some of the joy fom her walks.
This is the website that came up for me but I bought mine at a regular pet store (bad I know).
http://www.sitstay.com/dog/supplies/...73_26907_13272
But we've been taking my dog to training classes and have found a better alternative that works better and doesn't make her as depressed. It is called a prong collar.
It looks really mean and like it will hurt them but my dog doesn't seem to mind it at all. She will come to me when I hold it and let me put it on her but not with the gentle leader she'd try to run away.
The technique with the prong collar is that it is supposed to act like an alpha dog gently biting the submissive dog. It acts like their teeth. So as soon as the dog starts to pull you "pop" the leash up. But you have to do it real quick so that it doesn't hurt the dog, it just is a quick pop of the prongs. Some dogs in our class cried but the teacher said they weren't in pain they were just throwing temper tantrums.
This is a good article that generally explains it:
Dog Owner's Guide: The Prong Collar
I haven't read the article for this, but if you scroll down just a little there is a picture.
Google Image Result for http://bp2.blogger.com/_yJ6NLe1DBAk/Rgi9riGu5kI/AAAAAAAAAHk/tJTZC_9rRhg/s400/DSC04573.jpg
Sometimes my dog still likes to pull even with her prong collar and it makes me feel sad to keep popping it so I will make her sit and wait for a few seconds to calm her down each time she starts to pull. I think the important thing is to be consistent and let your dog know that you are the boss and they are going to do what you want. (walk nicely on their leash)
Good luck!