[X4U] Parental controls in Firefox?

[Mark Des Cotes]

Hi all,

My son is now old enough to stay home alone so I thought it would be  
wise to set up parental controls on my iMac G5 (10.4.11). I would  
like to limit what web sites he can view. I've figured out how to do  
it in Safari but he wants to use Firefox because of a couple of sites  
that don't play well in Safari. Is there any way, perhaps through a  
plug-in, that I can restrict Firefox to only sites I approve?

Thanks

Mark