The Login & Keychain Update 1.0 for Mac OS X 10.5 Leopard is recommended for all Leopard installations. It addresses issues you may encounter when:
*Logging in with an account originally created in Mac OS X 10.1 or earlier that has a password of 8 or more characters.
*Connecting to some 802.11b/g wireless networks.
*Changing the password of a FileVault-protected account.
What files does it affect?
/System/Library/Extensions/IO80211Family.kext/Contents/PlugIns/AppleAirPortBrcm4311.kext/Contents/MacOS/AppleAirPortBrcm4311
/System/Library/PrivateFrameworks/DiskImages.framework/Versions/A/CodeResources
/System/Library/PrivateFrameworks/DiskImages.framework/Versions/A/DiskImages
/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/OSServices.framework/Versions/A/CodeResources
/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/OSServices.framework/Versions/A/OSServices
Brcm4311 meaning the Broadcom 4311 wireless chip
I’m sure this is a stop-gap until 10.5.1