Thanks for the link! I think I'll give one of these a shot and see how it works with my iBook, I might even use it in the future for the PowerBook for wireless N networks.
The nice part about the Netgear aside from it being Wireless N is the design. Most of the USB adapters that worked with PPC were so oddly shaped that they either put pressure on the USB port when the laptop was sitting on a table, or were wide and blocked the use of the already limited USB ports that Macs come with. The Netgear WNA1000M does not block the other port and is small so you don't have to worry about it being connected to the port and it in a laptop bag for example. Keep in mind, that chipset is just a 1x1, so you are only going to get 150 Mbps at best. However, that is quite an improvement over the 54 Mbps that the AirPort Extreme cards could do. I am still looking for a adapter that is compatible with PPC that can achieve 300 or even 450 Mbps wireless N speeds.