Apple has released AirPort 3.0, which supports both AirPort Extreme and legacy AirPort products. Details on what changed in the updates are scant, but there are two versions available: one for Mac OS X 10.1.5 and one for Mac OS X 10.2 and higher.
Printing support in AirPort Extreme requires Mac OS X 10.2.3 or later. Check the AirPort Web site for a list of supported printers.
An Apple Knowledge Base article notes that internal Airport cards only are supported. Third-party cards can be used with AirPort networks, but Apple recommends using the software that came with your card to access an AirPort network.