Blocking certain sites [in Firefox]

[ShBm]

I want to block a few sites (YouTube, Facebook and MySpace among a few others) from being accessed on a computer. Is there a way to do this using an extension or Greasemonkey script in Firefox? Or is there another way, like doing something to the hosts file? In a perfect world, I'd like it to return a 404 error whenever someone goes to that site.

Thanks

 

[tomb08uk]

If your running through a router could do it via their, though that would effect any PC connected. Theirs a program called internetnanny or something like that, that allows limitations to be set.

 

[Red Naxelaster]

Yes, there is an extension that you can install which does this, called BlockSite, which works with Firefox 2.
The link is here: https://addons.mozilla.org/thunderbird/3145/

 

[way2evil]

http://www.mvps.org/winhelp2002/hosts.htm