Here are recent additions to The Best Resources On Talking With Children About Tragedies:
Talking to Children About Violence:Tips for Parents and Teachers is from The National Association of School Psychologists.
School Crisis Resources is from the NEA Health Information Network.
Coping with Tragedy is from The California Department of Education.
Talking with Kids about news is from PBS (Thanks to Richard Byrne for the tip).
How Do You Explain the Newtown Shooting to Kids? is from the PBS News Hour.
Statement from CEA President Sheila Cohen on Newtown School Shooting includes useful advice.
Not sure if you want every last thing that has been written about this awful tragedy, but my two sense are posted here: