WPA + FreeRadius + OSX
In a fit of masochism, I decided to secure my Airport Express WLAN via WPA and Radius authentication.
RADIUS authentication lets you manage access to your wireless LAN from a central RADIUS server, making it much more secure than storing authentication info on your wireless access points.
I picked up a pre-compiled OSX package of FreeRadius from <a href=http://carpestellarem.com/Products/StellarRADIUSLite.php">Carpe Stellarem.
There are a few other ways to get FreeRadius, including via Fink package, and by Andreas Wolf’s installer.