No 802.11g card will work under OS 9 with Apple-original drivers - if you'll recall, AirPort Extreme (Apple's name for 802.11g) was introduced in machines that wouldn't boot OS 9, thus only OS X (10.2.6 or 10.3+, I think) supports it.
There may be 3rd party G drivers, but I have yet to find any. I just use different cards for 9 and X if a particular card isn't supported by both.
For System 7.5-OS 9, I usually use Buffalo WLI-PCM-L11GP cards, which work in everything from the PowerBook 500 series and up with their drivers. I have a couple of ORiNOCO cards for machines that boot between 9 and X. For G under X, I have one of the Linksys cards mentioned previously, and a later-model Buffalo card.
There may be 3rd party G drivers, but I have yet to find any. I just use different cards for 9 and X if a particular card isn't supported by both.
For System 7.5-OS 9, I usually use Buffalo WLI-PCM-L11GP cards, which work in everything from the PowerBook 500 series and up with their drivers. I have a couple of ORiNOCO cards for machines that boot between 9 and X. For G under X, I have one of the Linksys cards mentioned previously, and a later-model Buffalo card.