The Child Exploitation and Online Protection Centre site provides many resources that may be useful to young people and educational professionals. They also offer a CEOP REPORT button for any harmful material and 'thinkuknow' educational materials for users.
http://www.ceop.gov.uk/.
The Thinkuknow site has many useful resources for raising issues and discussing concerns with young people.
http://www.thinkuknow.co.uk/.