The Unwritten Rules of Friendship: Simple Strategies to Help your Child make Friends by Natalie Madorsky Elman and Eileen Kennedy-Moore: This book describes the different ways children interact with their friends, along with guidelines for parents to help their child understand their strengths to help nurture friendships.
Raise Your Child's Social IQ: Stepping Stones to People Skills for Kids by Cathi Cohen: This book is based on social skills training programs to help with social skills and awareness.
The Bully, The Bullied and the Bystander: From Preschool to High School -- How Parents and Teachers can break the Cycle of Violence by Barbara Coloroso: Learn how the bully, the bullied and the bystander all feed into each other's reaction; how to identify signs; and how each type of child can be taught to change their part in this destructive cycle.
Some light hearted books to read with your children:
Cliques, Phonies and other Baloney by Trevor Romain, ages 9-12: This easy to read book keeps it silly while exploring a tough subject for kids.
Bullies are a Pain in the Brain by Trevor Romain, ages 9-12: The colorful drawings, fun style, and question and answer section are great to open up a conversation with your child.
King of the Playgroud by Phyllis Reynolds Naylor, ages 4-8
The Recess Queen by Alexis O'Neill, ages 4-8