The PCI card installs like a video card in a PowerMac and holds the PCMCIA card. The PCMCIA card is the equallivalent of the AirPort card. To use the PCMCIA card in a PowerMac you need the PCI card to hold it, but the PCMCIA card simply slips into the slot of a PowerBook like the Ti Book. Cisco refers to the PCMCIA card as the "wireless adapter". The pc cards, or adapters, that you would use with a laptop are plentiful on eBay and sell for $100 or less.

Here's an eBay auction for the pc card alone like you'd use in your laptop: http://cgi.ebay.com/ws/eBayISAPI.dl...item=2056064867

Here's an auction for the PCI card + pc card like the one I have in my B&W PowerMac: http://cgi.ebay.com/ws/eBayISAPI.dl...item=2056740554