Apple has posted
AirPort Extreme Update 2007-003. It’s available for download from Apple’s Web site and from the Software Update system preference.
Apple recommends the update for all Intel-based Macintoshes. It includes compatibility updates for third-party access points configured to use Wi-Fi Protected Access (WPA) or WPA2 security protocols.
System requirements to apply the patch include Mac OS X v10.4.8, an Intel-based Mac and AirPort Extreme Update 2007-002.