Try out PC Chaperone (
http://www.pc-chaperone.com)
I've done a lot of research on parental controls and have found this
to be the easiest and most flexible of any. It has more features then
any other program and some that I haven't seen anywhere else, like the
ability to set limits on how long a user can view a specific web page.
I use this a lot to control the amount of time my kids spend on
myspace and facebook since it doesn't affect limit the time they can
spend on other sites