I had the luxury (and headache over several days) of trying several wireless card/software combinations to get my Powerbook Firewire 2000 machine to work without spending big bucks.
SUCCESS (at last):
Card: Netgear MA-401 (a generic-type PC card available at mass retailers).
Software:
http://www.ioexperts.com.
A terrific site, which will break down the actual versions of various cards you may want to try regardless of the driver you choose. The minimal bucks you will spend will attach itself to the wireless CARD you buy, rather than the computer chassis itself, i.e. your investment will follow the card, not the laptop.
Worth the effort muchly. Not affiliated with any vendor, but always glad to pass on success stories if they can be of help to others.