I tried to get WPA wifi working on Breezy Badger with a Amilo M7400 laptop a while back and although it worked in the end, it was a bit of a nightmare getting there. However, it seems that with the new Dapper Drake release they have made the process a little easier with the network-manager-gnome package. Read this article on Ubuntu Dapper Drake and WPA-Encrypted Wireless at fredericiana for further information.