AirPort in Mac OS X 10.1 does not provide a software base station feature.
To share locally between computers, you can still easily create a computer-to-computer network by choosing Create Network from the AirPort menu bar icon. If you need Internet connection sharing or other features provided by software base station, consider purchasing an AirPort Base Station. The dedicated AirPort Base Station offers additional features not provided by the software base station feature of Mac OS 9. For more information, see the AirPort product page (
http://www.apple.com/airport/).