Yes there is one, and it comes with drivers. A client of mine bought it for his Orignial iMac. He found it by searching through pricewatch.com. I believe is was made by either Orange Micro or Smith Micro. Nice thing. About the Cantenna thing, you can buy an "thingy" to hook between the Card and the internal antenna, and then run it out the side of the iBook through a side vent. I'm thinking about the cantenna thing with my TiBook, and fortunately, I can use the PC-Card Slot to lead the antennal lead out of the machine. I'd just like to be able to buy one already made, ready to go, just Plug-n-Play.
New Product idea.... iCan - Antenna Extender for Airport and Airport Extreme Enabled Macs.