The best parental control is signing up for Fluther and see what your kid’s asking ;-)
Of course, what you could do is install some auto-clicker to add noise to the log (i.e. visits so many websites that they can’t discern the porn websites you’re visiting – unless they have striking names, of course, that could be retrieved by a quick search for, say, “porn”. Then again, you could prevent that by visiting it through a mirror, though then yet again they might search for page titles as well).
Sorry conerning parents ;-)
Also, obviously, this idea just sprang to my head without me ever having tried it myself.