Hi, DrSirus. There are a number of PCMCIA Card wireless adapters, both 802.11b and 802.11g, that use the Broadcom chipset which is fully supported by Apple's own Airport software. No third-party drivers are required with those cards. They include Sonnet's
Aria Extreme, which in my own experience has been 100% plug-and-play, even in a Tibook that already had an Airport card installed. There are also these two
MacWireless cards, one of which has provision for an external antenna extension to increase its wireless range. All three of these have been highly recommended by posters far more expert in this area than I am. On the strength of those recommendations, I bought my daughter an Aria Extreme for her Tibook 867, and I also tried it in my Airport-equipped 1GHz Tibook. It worked beautifully in both.
For other possibilities, see
this table, and look for PCMCIA cards that are supported by Airport. Some of the cards listed may be much more widely available than others.