I agree with Jonesy about using an eCollar to teach them the boundaries. I needed to train my pup to stay in the yard at my in-laws. He is usually over at their house at least once a week, and needs to lean how to stay in their yard. Luckily the boundary of their yard has some natural features for the dog to recognize. I first took my dog around the yard everytime we were there on leash. We walked the boundary of the yard about 5 times. After a few sessions of this we walked the yard 2 times on lead, and then I let him loose with only a check cord dragging behind. We walked around the boundary, and when he started to go beyond I corrected him with the check cord. We did this a few times and he was really in tune with staying in the boundaries while I was walking near. I then put his eCollar on him and did the same thing, only I stood near the middle of the lawn. I corrected him by voice and shock at the same time. After a few sessions of this, I was able to sit inside the house (thank god because it was winter time and pretty cold) and watch him. I would give him a zap if we went past the boundaries that we had set up. Now I can let him out and don't think twice about him leaving the yard. If another dog comes near their yard or any other distraction, he just sits at the boundary and barks or stares. It only took a total of about 1 month which I thought was pretty good considering we didn't get to work on it but a couple times a week. I am sure if I was trying this same technique at my own house every day he could pick it up in a couple weeks.