If you don't want to shell out a couple hundred bucks for an AirPort base station (and you happen to have another Mac lying around not doing anything), you can set up a software base station on that other Mac — provided it has an AirPort card installed. The base station software can function in the background while someone else uses the computer for other tasks at the same time. After you install and configure the AirPort base station software, the computer provides much the same capabilities as a freestanding base station. For example, a PowerMac G4 running the base station software can provide wireless Internet connection and can interconnect wireless Macs on a wired network.

A software base station is attractive because you don't have to buy a separate piece of hardware, but it has several downsides. For one, a software base station is more complicated to set up. Also, the Mac on which the software is running must be left on so that other wireless Macs can connect to the network. The software also uses some valuable memory and processing power on the Mac, reducing the Mac's performance. And lastly, you probably won't be able to reposition the host Mac to optimize the wireless network signal as easily as you can the freestanding base station.