Apple has released an update for its AirPort Express unit. Version 4.0.1 improves Profiles support and handling of WEP keys with third party access points. From Apple:

This update is recommended for all customers with AirPort Express base stations.

[...]

What's New in this Version

Improvements to Profiles support in the AirPort Admin Utility
Improve handling of WEP keys with third-party access points

AirPort Express Update 4.0.1 weighs in at 1.1MB, and is available now from OS X 10.3's Software Update pane. A Windows version of the software is also available, weighing in at 7.5MB. Both versions are also available at Apple's Downloads page.


Source : Mac Observer