Apple's Airport Extreme card is an 802.11g wireless networking card which is compatible with a range of Macs produced. The card fits in a dedicated slot, which is different to the original Airport card's, so this card is only compatible with the Macs listed below. The card is controlled through Apple's own Airport software in OSX, making setup and operation simple.

Apple Airport Extreme Card - Network adapter - 802.11g

• Connect to the Internet or other computers without wires
• 802.11g technology
• 54Mbps data transfer
• Requires compatible Apple Mac and Mac OS X v10.2.7, Mac OS X 10.3, Mac OS X 10.4, Mac OS X 10.5
  
  This Apple Airport Extreme Card is compatible with the following Apple computers:
  
• Power Mac G5
• Power Mac G4 (FW 800)
• PowerBook G4 (12-inch)
• PowerBook G4 (12-inch DVI)
• PowerBook G4 (15-inch FW800)
• iMac G5
• iMac USB 2.0
• iMac 17" 1GHZ
• iBook G4
• eMac (ATI Graphics)
• eMac (USB 2.0)