We started using an allowance system that a behavior therapist gave us. You give the child his/her age in allowance on Saturdays. Then you make them pay for privileges (tv, computer, playdates they request, movies) if they request them (as opposed to when you plan them), you have them pay for specific bad behaviors that you have outlined, and you pay them for good behaviors that you are trying to encourage. You can give them goals to work towards, etc.
This system seems to be really working because it puts the power in the kids' hands. They get to choose how to spend their money. They know bad behavior costs them money. They start to be more aware of their actions.
Good luck!
