Internet filter with password

Is there a free internet filter/net nanny that I can download that will let me block specific sites of my choosing. When said specific sites are typed in, it will prompt you with a password if you want to go there (I want to stop my sister from accessing facebook unless at certain times approved by my parents, when they will just enter a password and then let her use it for a certain time period). Also needs to apply to all user accounts on this computer.

Any programs like this out there?

I have no experience with the free ones, but Norton Internet Security has pretty comprehensive parental control tools, I think.

I'm not sure of any free software that can work on time limits etc... but there are free ones that will block it completely. I have a search tomorrow and see if I can find anything that can do this

I've had a look around today but can't find anything to do this (that's free anyway) - you might need to go for a paid version to get this, unless you've found something already?

It's possible to do this at the router/gateway level in some cases, and with some third-party firmwares. Tomato, for example, which I'm running on a WRT54 has it.

Thats what I was going to suggest.

What Codex and Zeus said, I'm running DD-WRT at home and it has time limits/website blocking/keyword filtering.

Hmmm, will that method just block certain sites permanently (unless the settings are changed in the router configuration page)?

If possible I'd like a password prompt to appear when selected sites are accessed, and without the right password you can't access those sites. Not sure if something like that exists though...

Of course it does. Just not for free.

The Tomato interface at least allows you to schedule access to sites specified, for example allowing Facebook only during certain hours each day.