Using Airport to connect a G4 Mac and an iBook (connected to the net via BT ADSL)…

I’m looking for advice (and/or links) on how one might go about sorting out the wireless networking of one G4 desktop Mac and one lovely sexy-new G3 iBook (both running OSX 10.2.3), the former of which is currently connected to the interhighweb via an Alcatel USB ADSL modem and BT Broadband. Some of the possibilities that I’ve been presented with so far: