Apple were the first computer company to embrace wireless networking.

Airport Card:
The first apple wifi card was called the "Airport Card" It was released on July 21, 1999 at the Macworld Expo in New York. The card was wireless IEEE 802.11b compatible, with a range of 150 feet and transfer speeds of upto 11Mbps.
This is the ideal wardriving card for any of the older apple laptops as it works in
passive mode with wifi cracking software such as KisMAC.

Airport Extreme Card:
On January 7, 2003, Apple introduced AirPort Extreme the updated version of the existing card to Airport card.
AirPort Extreme is 802.11g and provides a range up to 50 feet at 54 Mbps and up to 150 feet at 11 Mbps
The Extreme card is wireless 802.11b and 802.11g compatible.

Even though both Airport cards are made by Apple, they are still completely compatible with any other wifi network (including Windows & Linux networks!) so long as they are 802.11b or 802.11g.
Basically Apple uses "Airport" to personalise there wireless range and separate it from other brands.

People often ask whether it is possible to fit a Airport card in an Airport Extreme slot or vice versa, the answer is unfortunately no.

USB:
If you would like a cheaper wifi card for your Mac, you can always buy a USB wifi card. Not only is this cheaper, but if you can take it out and switch it between computers.
Be sure to check that the USB wifi you're going to buy is Mac compatible, or their is an available Mac driver that you can download for it, and also if you want to crack networks using KisMAC, make sure that it has a Prism2 chipset.
I personally use the D-Link DW122 USB dongle and it works great with KisMAC because it has a prism 2 chipset.

PCMCIA or PC Card:
If you are one of the lucky people on this Earth who have a Powerbook or MacBook Pro, you could go with the PCMCIA (Personal Computer Memory Card International Association) option. I personally would go with this option because most PCMCIA cards have an external antenna slot (like the Proxim Orinoco cards) which let you plug an antenna straight into it. The best PCMCIA cards to buy which are fully compatible with KisMAC are from Proxim such as the Orinoco Gold Card, they also have great built in range and are compatible with wardriving software from other operating systems such as Kismet running on Linux.

For more info on Airport, visit Apple's Website