App to block access to certain sites

Dear Coders, I need a simple app that blocks access to certain sites (configurable). The first time it is run, it should prompt for an administrator password, this password is required anytime the user wants to change the app settings. The app should run at start up and can't be killed. Also, I need the user to be able to try the software for certain days before they are required to purchase a license. That's all ! ## Deliverables * * *This broadcast message was sent to all bidders on Wednesday Apr 21, 2010 8:45:29 AM: Note that I don't want a program that edits "hosts" file, you must think of something else.