Apple has released two updates affecting Airport; you only need install one, following the guide below, or by using the Software Update utility (available in the Apple menu). Your OS build number can be found by choosing "About This Mac" in the Apple menu, and clicking once on "Version 10.x"
AirPort Update 2006-001 will install on the following systems:
Security Update 2006-005 will install on the following systems:
What's new in this version:
Security Update 2006-005 is recommended for all users and improves the security of the following component.