According to this, the airport card slot on an iBook G3 is just a regular PC Card slot.
I was wondering if anyone here ever tried a third-party PCMCIA Wi-Fi card -or even other PCMCIA cards, like a USB adapter- and if something like this would work, disregarding obvious size differences.
Well, there's this - https://www.geektechnique.org/projectlab/662/diy-airport-for-that-old-ibook.html - where someone used a Lucent card in his iBook, but still only 802.11b and still not able to connect to modern secure networks.
I think you can probably get a genuine Airport card for less these days, with no hacking around
As for other PCMCIA cards, even if you could cut one down enough to fit, there's no way to get at the interface for say, a card with USB ports.