It also seems that passwords hashed on 10gR2 and lower where the database has been upgraded to 11g will retain case insensitive passwords. This hints at the old DES based password algorithm still being available in 11g as well. I cannot confirm this as I am not a beta customer (indeed if I was I couldnt confirm it either!) and I am sure my source isn't either but they found out quite reliably so i am sure its correct.
This is good news that Oracle seem to be taking security very seriously in 11g.