Hi... I have exactly that problem... By the way, all this is related to using an Intel based MacBook Pro... On Tiger I never upgraded beyond 10.4.9 because I heard about a lot of issues with 10.4.10... And on 10.4.9, I was able to use WPA encryption with my Netgear router, no problem... However, being the early adopter of new OS's when I installed Leopard, from the getgo I lost the ability to connect to my Netgear router with WPA... WEP or simply shutting encryption off, however, works fine... What's more interesting is I have an older Belkin router and on a lark I hooked it up and tada, WPA works fine with Leopard... I did check to be sure I had the latest firmward for the Netgear router and I do... I have other problems using the Belkin router so for now I have switched back to the Netgear router and simply use WEP until I figure out some fix...
To say more about what actually happens when I try to connect to the Netgear router using WPA (or WPA2) when I attempt to do so, it ALWAYS asks me to enter the password even though I long ago told keychain to remember this password and to always allow... I enter the password and click OK (or whatever the prompt says). I usually then get "connection failed" after a few seconds... Once in a while I get "invalid password" (though I know it's the correct password)... What's most interesting is if I just keep trying by just continue to click OK or try again or whatever it says (all this without reentering the password but instead just leaving it as it was originally entered), after say four or five tries, it WILL SAY IT'S CONNECTED... All indications show that it connected successfully and if you run the Network Assistant, it will say the same thing, ie., that you're connected ok... But in fact, you're not connected at all... if you try to access anything on the internet, it fails... Strange... So back to WEP I must go...
Anyway, clearly there IS some sort of issue between Leopard and CERTAIN routers, in this case and it sounds like what Apple told you also, NETGEAR routers...
That's my story... Any wisdom from anyone would be much appreciated... thanks... bob...