We have an old TiBook 800 that was sitting around after I moved the network from WEP to WPA encryption. The Airport card built-in the old Titanium Powerbook did not support WPA or higher encryption. So, I went looking on the net and found a lot of old information on cards that would work with OSX but most of those PC cards were no longer available and all the posts across the net were pretty old.
So, I went down to Besy Buy and got a couple to try hoping I would find one with a Broadcom chipset. Good news is that I did find one and OSX sees it natively as Airport Extreme. The card is a Dynex Wireless G Notebook card. It was $60 or so. The TiBook is running Tiger and is a great laptop outside of the networking limitation because of the orginal Airport card. I plugged in the card to the PowerBook and went the network control panel and it recognized it as a new Airport connection. I rebooted and it took over as the Airport Card.
More information on it @ http://www.dynexproducts.com
It is a great solution to give the older PowerBook a new life.