The National Child Traumatic Stress Network (NCTSN) has resources for talking with children about the recent shooting in Connecticut. There are also resources useful for parents.
Resources for Response to Connecticut School Shooting: •Talking to Children about the Shooting •Psychological Impact of the Recent Shooting •Tip Sheet for Youth Talking to Journalists about the Shooting •Tips for Parents on Media Coverage •Parent Guidelines for Helping Youth after the Recent Shooting
These can be found on the NCTSN website and PDFs are printable at The National Child Traumatic Stress Network.
The American Psychological Association has additional resources: