There is a harness called "Gentle Leader" which goes around the top part of a dogs head, and snout. It is an easy training tool to use with a dog, as it controls the head. We still use it on two of our largers dogs as it is a control issue.
Google Gentle Leader for more information. FYI make sure to get the right size. We actually took our boys into Petsmart and got help from their trainers to fit them.