Airport Extreme (IE, the 802.11g wireless in non-9 compatible PPCs) is electrically mini-PCI, not PCMCIA, and it's mechanically proprietary so you may have issues trying to plug a normal MiniPCI card into it. (It's an experiment I've never heard having been tried.) Unless someone knows of a PCI wireless chipset with 9 compatible drivers that also happens to come in a mini-PCI version I think you're pretty much starting from scratch here.