MS Proxy and Internet Access

Hi,
I am planning to install MS Proxy 2.0 on a Windows NT4 SP6 system, to provide Internet access and Firewall for a small group of people in my office.
I know that MS Proxy provides http, https, ftp etc. support, by default on Port 80. Can I change http access to port 8080, https to 8081 and so on? Is it possible on MS Proxy 2.0? If so how do I do it. Please let me know.

Thanks,
Jayanth