This article, When and How to Negotiate with Your Kids, from the website The Successful Parent, is a great resource for information on how to help children learn to communicate effectively. The article starts off describing why to use negotiation:
"Negotiation is a valuable tool to use with your kids because helps them develop some important skills. Most notable are:
Those are good skills for kids--and adults--to learn! It's a quick and easy read, worth the time to read and definitely worth the time to learn how to do with your kids!