Some useful Websites:
Internet Matters: http://www.internetmatters.org/schools/primary/
Safer Internet: http://www.saferinternet.org.uk/
CEOP: https://www.ceop.police.uk/
Safety Net Kids: http://www.safetynetkids.org.uk/personal-safety/staying-safe-online/
Think U Know: https://www.thinkuknow.co.uk/
KidSmart: http://www.kidsmart.org.uk/
Some useful resources:
E-Safety Tips for children 0-5