This site for parents is excellent at providing strategies to assist parents through common problems. For example, sibling rivalry is a natural part of growing up. Here are the strategies they gave to save your sanity and turn the typical behavior into a wonderful learning opportunity for your kids:
"•Stay out of the problem whenever possible. Avoid teaching your children that fighting with each other is a good way to get your attention.
•Say to them, “It looks like you guys have a problem that you need to solve. I’ll be happy to give you some suggestions about solving this problem when both of you are calm.
•Separate them if necessary.
•If your kids continue to hassle your eyes and ears with fighting, say, “I’m going to have to do something about this. We’ll talk when everyone is calm.”
•Expect them to replace the energy they drained out of you by doing extra chores, hiring a babysitter so that you can go out and relax, staying home instead of being driven to their friend’s houses, etc."