Wireless Networking with a Macintosh
Macintosh wireless networking follows the same principles as those used in a wireless PC network. That is, it uses the 802.11b or 802.11g protocols for hardware and software to establish the Wireless Local Area Network (WLAN). Because Apple did the initial design work of what was to become ratified by the IEEE as 802.11b, it is not surprising that the Mac did wireless before PCs did.
Simple Networks for Simple Situations
The great majority of Mac WLANs are simple, which means that they are used to connect a single Internet connection (DSL or cable; it doesn't make much difference) to one or two computers through the use of an Airport "base" station and an Airport card in the computer. The "Extreme" Airport base station works with the 802.11g protocols, which is faster (at a range of fewer than 50 feet or so) than the non-extreme Airport base stations that use the 802.11b mechanism of connection. But the range of most Airport networks is about 150 feet to maintain a connection. Your site condition can vary this range significantly from the maximum.