i've bene curious about running a RADIUS server to provide per-user/reasonably secure authentication (as opposed to WEP) for access to a wireless LAN (and dialup perhaps) and RDXServer (Cross Platforme Radius Authentication) (um, i don't think there is an "e" in "Platform...") looks like the only option i see. this article in the apple kb provides a quick explanation of WEP vs WPA (Wi-Fi Protected Access) in OS X.