Is there any chance that x3watch will become available on Linux? More specifically Ubuntu Linux?
You can get Dansguardian to work on linux and there is a christian version of Ubuntu with it already installed.I know this doesn't answer you're question, but I hope it might help some how.
I wouldn't count on it octotom, but it there is something in the works here: http://ubuntuforums.org/showthread.php?t=550287 I haven't tried it, so can't really say how well it works. Hopefully it is of some use to you.Dansguardian doens't work as an accountability program, though it is good for filtering. Install it if you don't have it already using this howto: http://ubuntuforums.org/showthread.php?t=207008
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