The below sites contain information and applications for protecting minors from problematic online content.

Cyberangels: World’s oldest and largest Internet safety organisation
GetNetwise: Educating parents and children about how to use the Internet safely
KidShield: Tools and information to create a safety net for your children online
ProtectKids.com: Protecting children in cyberspace
SafeKids.com: Making your family’s online experience fun and productive
WiredKids: Online safety for kids and teens