Airport Card Update 2004-08-31
Now available via Software Update:
AirPort Card Update 2004-08-31 improves reliability in mixed 802.11b and 802.11g environments and is recommended for all customers with AirPort-capable computers running AirPort 3.4 and later, including AirPort 4.0.
After this update, the AirPort Driver and AirPort Extreme Driver will each be upgraded to version 3.4.3.
Apple AirPort website at www.apple.com/airport
Apple Support website at www.apple.com/support
Apparently there is a Windows version of this update as well available via Windows Update.