Thanks for responding! My primary motivation is to monitor my teenager's activity, secondly I would like both my boys to have access to the printer.
I would say what you want is a way to view your network activity, something like a network proxy or a tool to locally lock down websites on the boys' computers.
The way I usually go is to use OpenDNS (http://www.opendns.com/).
It is just a quick entry into your main router and 'poof' all your comps are using it and you can get detailed reports of websites. It also allows you to block sites from people accessing them.
Hope this helps a little with one of the two issues.