You can purchase Parental Control Software. Such as: http://www.kidswatch.com/
KidsWatch™ Family Protection Suite is your fastest and easiest solution to safeguard your children's Internet experience and maximize the efficiency of the time they spend on the computer.
Parents can set computer usage time limits, by child; ensuring homework is a priority over:
* Internet Chatting and Online Gaming
* Social networking sites such as YouTube, facebook, adult sites and more
With the knowledge and confidence that KidsWatch is protecting their children from the dangers of the Internet by…
* Blocking access to dangerous and inappropriate web sites.
* Alerting the parent immediately when a child steps outside the boundaries of safe surfing. KidsWatch™ will automatically send you e-mail alerts when your child enters or receives a suspect phrase or keyword from any chat conversation. You are alerted to inappropriate conversations, risky situations, child predators, conversations containing sex, suicide, drugs, guns and more.
* Monitoring and reporting on chat activity
KidsWatch™ is much more than the best-rated Parental Controls solution. It is loaded and preloaded with many optional benefits and features that improve the security and the quality of the Internet your children see. Installing KidsWatch™ on your computer is customizing the Internet, by child, the way you want your kids to experience and use it.
Give it a try!