WPA (using 802.1x not pre-shared keys) or 802.11i when it comes out.
http://www.wifialliance.com/OpenSection/protected_access.asp if you don't know much about WPA.
Assuming you are using the Centrino card, the Intel drivers had issues with WPA after waking from standby but the newest drivers are supposed to fix it... So maybe they are still buggy.
You have to register your MAC address at my school too. Without it the DHCP server won't lease you an IP. Sometimes you can just put in a static IP and it will work tho...
Microsoft has a small article on using WPA with Windows.
http://www.microsoft.com/WindowsXP/expertzone/columns/bowman/03july28.asp
Can you elaborate a bit please? The only info I can find about WPA (insecure wise) is that short and/or dictionary type keys are brute forceable which is...
Its easier to spoof a mac address than to break WEP.
Turning off the broadcast doesn't mean no one can get your SID.
Just use something like WPA instead.