Having seen this and similar questions a number of times, I'll finally stop being lazy and put in my $0.02.
I have found it useful to use the same nsd.tcl file to run both ACS and OpenACS. It is called from another tcl file, which you can name anything you want (I'll call it "service_name.tcl"). It actually works pretty well for me. Just edit and rename service_name.tcl for each of your ACS or OpenACS services (I also run non-ACS stuff with these config files as well). To start a service, just use the command (from your aolserver home directory):
./bin/nsd -t ./service_name.tcl
Make sure both service_name.tcl and nsd.tcl are in the same home directory (actually I have a separate directory for all of the service_name.tcl files -- just make sure you apply the command above with the right path to service_name.tcl).
I will post both nsd.tcl and service_name.tcl here to follow. Experts please feel free to critique these if you see any improvements and/or comments you'd like to make.