You don't need RADIUS servers for WPA, its an option in the spec. Preshared keys of suffiecient length are fine.
And it is better than WEP assuming you use AES and not TKIP.
Mark, you should look into the Proxim (Proxim.com) and Buffalo (BuffaloTech.com) APs, they both have AES hardware and work well with WPA. Be wary of building WPA networks though, because you want to have only WPA hardware on it, otherwise you have to fall back to WEP for the network, and you're in another boatload of trouble.