This is something that I got from another homeschool mom, but it could work for anyone. It has truly changed our house. We still have minor issues, but at least there is a set punishment and also reward system in place that everyone knows about. The kids have DRAMATICALLY changed their behavior and attitudes toward us and each other.
It works like this: Each day they start out at a 3 and they move up and down depending on their behavior and obedience. Each number has a list of what is aloud at that level, and there is also a list of things that move them up and a list that moves them down. At our house if they are at a 5 when they are headed to bed they choose something out of the prize box. It has coupons for different things like time with mom and dad alone, free chore, 30 min. of TV or computer game time, and also there are dimes, 10 cent candies, and 10 cent toys or stickers. The kids love being rewarded at the end of each day(if they earn it) and we love the consistancy.