I am a frequent watcher of the show "Barking Mad" on Animal Planet, this is an animal training ahow and they deal with barking all the time. They really stress positive reinforcement, for example:
They recomend having a training clicker (Available at pet stores like Petco) and treats, when the dog is behaving (not barking reward with a treat while clicking the clicker. This helps relate the sound to the reward. When the dog is barking you ignore it and wait for a break in the barking (when he is quiet for a minute) to reward the silence.
This method may be hard to understand in a written post but it has been effective with my Max. For a better idea of wht the technique involves I would recommend watching "Barking Mad" on Animal Planet, here is the website (the listings are on here)
Animal Planet
Good Luck!