there is a list of pcmcia card that are supported.
I've already managed to get several pcmcia-ethernet-cards to work under linux (netgear, xircom...) on various distro's, most distro's will detect pcmcia cards automatically and load the fitting module. Sometimes this has to be done manually, but that is rather exceptional. In fact, uptill now I don't remember any pcmcia card refusing to work on one of my laptops, so go for pcmcia!
ps At this moment I have a orinoco wifi card working on an G3 powerbook running debian.