(Free) web filtering software

[riddlermarc]

I'm having to set up my Mum's pc with a net connection for the first time, but the problem is that my nephews often use it so I want to put some filtering/security on it. I know yo can purchase Net Nanny etc but I was just wondering if there are any open source/free ones out there? I looked at Naomi (http://radiance.m6.net) but it seems that it will just auto-close the browser if you hit a dodgy site, even accidentally.. could be a real p.i.t.a..

 

[TriedandTested]

http://www.censornet.com/ but needs it's own PC to install on i believe.