At work I have a netbook running Ubuntu Netbook 9.04. At one point I changed my login password, and then wanted to set up our test WPA2 network on it. It prompted me for my keyring password, which was very frustrating since I apparently didn't know that.
If you change your login password on (at least) Netbook Remix edition, it won't change your keyring password: see heah for screenshots etc.
GJ Ubuntu.