As is the case with some other folks I, too, had no problems using WPA under Tiger but cannot connect with WPA under Leopard, at least not when using my NetGear WGU624 router... WEP works fine but not WPA.. When I try WPA, after some number of "connection failed" attempts it eventually will report that I connected successfully but when I try to access the internet, nothing... I also own an older router that I previously had stuck away in a closet, a Belkin F5D7230-4... This weekend I got it out and hooked it up to see if I got different results. And the answer is yes, both WEP AND WPA worked fine.... But I have other issues with that router accessing a security camera I own so for now I am staying with the NetGear and running WEP...
Bottom line is there is some sort of an issue coupled between using Leopard and CERTAIN BUT NOT ALL wireless routers... Plus I see other posts where folks are having an opposite problem, an issue with WEP where for them WPA works fine... Seems like an assortment of issues all of which have been generated since switching to Leopard...
Just tossing my experience into the mix in case that triggers anyone to guess at a possible reason which might lead to some solution... Thanks... bob..