With all due respect Pastor Lewis, the problem with net nanny software or even the program you describe is unintended consequences. The most common one is the settings are set and will not allow you or your wife to access sites you have a legitimate need to preview. We have had that issue at work. Our IS department set up filters to exclude ebay and similar sites. We could not access Mapquest (for which there is a genuine legitimate business use). The settings had to be reconfigured so nobody can access Yahoo, AOL or ebay. This is easy for a team of professionals getting paid to do this but for a family? A waste of time and money. For an example of an unintended consequence consider Craig's List. We buy inexpensive but useful stuff from there and avoid the rants and raves (lots of bad words therein). If you use Net nanny or some other filtering software or OS, how likely is it that Craig's List will be excluded due to the bad words in certain areas on the site? Same goes for Amazon.com. There are some horrid titles there but there are also a ton of Christian books and resources there. Would not the Ubuntu and Net Nanny also exclude that site?
I understand your concerns about the internet and find it frightening when children are not supervised while net surfing because mom "trusts her kiddies". The same problem would apply to reading materials. I would hope any books coming in your home would be scrutinized as much as the internet. And that anyone working with your covenant children are background checked and fingerprinted. I am not being sarcastic but am dead serious. Pedophiles are NOT confined to cyberspace.