The Internet doesn't have to be a dangerous place. Here is an introduction to setting up software on your omputer that can keep the bad stuff out.
You can review many filters at http://internet-filter-review.toptenreviews.com/ 

One of the most basic safeguards against temptation online is installing a filter that can block pornography from coming into your house. This article discusses some of the basics of setting one up for your home.

After testing several of the options out there, our favorite filter is a free one. K9 Web protection http://www.k9webprotection.com/ is the free version of an advanced corporate solution, and has more powerful options than any of the others we have tried. Recommended for any Jewish home with Internet access. 

From the National Coalition for the Protection of Children and Families. In short, the psychological and spiritual damage done by looking at porn creep in gradually over time, so that a person who indulges for the first time will not be aware of the profound impacts it is having on him.

Brilliant piece exploring the root of Internet pornography addictions. Really, it all comes back to a desire for intimacy. To the Kabbalists, the desire is even deeper- an existential longing to cleave to Hashem.