Ok, so I seem to have this figured. Sort of.
The last two utilities in my first post are those that come standard on new Macs. They are also included if you install the new Airport Extreme Station.
If you have the latest iMac (this also applies to other current Macs), but purchased it before the new Airport came out, you are stuck with the old software applications.
What gets me, is that I never installed the software for the new Airport Extreme and currently use the older 802.11g one (No pre-draft 'n').
Why therefore, should I have to use different software to configure it on different machines which both have the latest OS and are both the latest offerings from Apple? I find it very, very strange that Apple should assume that all customers of the newer Macs will own a new Aiport Extreme also.
Lastly, why don't they make available the two newest utilities free online via software update as they seem to be capable of using the older base station?
David
EDIT: The older version, 'Airport Admin Utility' is version 4.2.3 and the newer, renamed version 'Airport Utility' is version 5.1. They have completely different interfaces.