Paul,
You can have this in your nsd.tcl (I think this is how the sample nsd.tcl on the openacs documentation does it actually):
set hostname [ns_info hostname]
set address [ns_info address]
Then use the $hostname and $address Tcl variables everywhere they are needed. Notice that you'll have to restart aolserver for new addresses to work.
However, you could have AOLserver always listening on localhost/127.0.0.1 and your dynamic IP wouldn't matter.
