Tracking Users accessing Internet

I have a Proxy Server running Proxy 2.0 on a NT4 machine. All my users access the Internet thru’ the Proxy Server. I want to be able to track which user is accessing what sites on the Internet. I want to be able to capture, the computer name and thelist of sites this computer accessed during the course of the day, as well as the time spent on the Internet.
Appreciate your help, Rgds – Trent