WPA is functional in CURRENT for some time now:
http://undeadly.org/cgi?action=artic...20080416195151
It worked OK with bwi(4), malo(4), ral(4), iwn(4), wpi(4), ural(4), rum(4), upgt(4), and zyd(4) chipsets but that's April news... it should cover many more chipsets by now.