Airport is the name for Apple's wireless hardware. Airport is 802.11b
which was replaced by Airport Extreme which is 802.11g. Apple have just released a new 802.11n Airport Extreme Base Station.

802.11n Airport Extreme Base Station

802.11g Airport Extreme Base Station
These guides refer to the older original 802.11g Airport Extreme Base Station and the Airport Express. Most of these guides will be relevant when using the new base station.