I don't understand the appeal of this AirPrint. Why does a printer have to be wireless? Nobody carries a printer around with them, it's a stationary device, ideal for wired connectivity. Networked printers have been available for decades. Even my little desktop Laserjet 1300n has a JetDirect ethernet card in it, and anyone can print to it from their wireless laptop.
Plus if you have a wireless device (laptop, tablet, etc) in your home already, that means you have a wireless network already. Why do you need AirPrint to print directly to the printer, when you already have a wireless network that can carry the traffic for you?
AirPrint seems like the answer to a question nobody asked.