Services on different ports. To run a different service on another port but the same ip, simply repeat Install OpenACS 5.1.0d2 replacing service0, and change the

set httpport              8000
set httpsport             8443 

to different values.

Services on different host names. For example, suppose you want to support http://foo.com and http://bar.com on the same machine. The easiest way is to assign each one a different ip address. Then you can install two services as above, but with different values for

set hostname               [ns_info hostname]
set address                127.0.0.1 

If you want to install two services with different host names sharing the same ip, you'll need nsvhr to redirect requests based on the contents of the tcp headers. See AOLserver Virtual Hosting with TCP by markd.