Just barrier training. Do a lot of recalls, but allow them to be released once you've called them back to you (giving a treat is reinforcement, but the really good reinforcement is letting them go back to what they are doing) I do a lot of this at dog parks. Jackpot reinforcements for whenever they voluntarily come up to you. Being able to call your dog off anything they chase is also what helps. My dogs tend to check in with me if they get about 20-30 feet away.

It also helps to begin letting your dog have freedom, a long line can help. A very thin one so it feels like they are off leash but you are still able to have control over them. Being off leash can't be a novelty to them or they will take advantage of it every time. My two have been off leash a lot since I got them as puppies. You should also graduate to letting them drag the long line so you can at least step on it if you see them begin to get too far away.

Some breeds will definitely have a harder time with it, but my good friend has ibizan hounds (sighthounds) and they do amazingly well off leash. Some of the best dogs I've seen. She is able to recall them off anything they begin to chase. It takes a LOT of dedication and a LOT of training. But she has it and she did it.

Just googled it quickly and found this article. I generally like her advice in it.

http://dogtrainer.quickanddirtytips....d-rewards.aspx