Not quite sure that interarchy you talked about has anything to do with packet sniffers. That was only after a very cursory google search, however, and I may be wrong.
Some software I have managed to get working on my busted-ass G3 "Snow" iBook:
Ettercap -
http://ettercap.sourceforge.net/
Ethereal -
http://www.ethereal.com/
KisMAC -
http://binaervarianz.de/projekte/programmieren/kismac/
Kismet -
http://www.kismetwireless.net/
Apart from KisMAC, the software mentioned above required an extraordinarily steep learning curve as regards command-line business. I used a program called Fink Commander to babysit me through anything more complicated than changing directory. I also needed to install X11 to get Ethereal to work, mostly achieved through good luck, reading a lot and prayer.
Fink -
http://fink.sourceforge.net/
X11 -
http://www.apple.com/macosx/features/x11/
Hope that helps a little. This is by no means definitive or authoritative, only what I have managed to get working and vaguely understand.