[sclug] howto - set date format to YEAR-MM-DD

[Graham]

How can I switch date format to YEAR-MM-DD
The current format is DD/MM/YY in
evolution/contacts/(someone)/personal-info/Birthday

evolution 2.6.1
ubuntu 6.06
gnome desktop

I sort of hoped it would be a preference for all apps
on the desktop, but I cant find it.
Its OK if you know for a later app/desktop/distro
I was going to ask on weds, but wont be there,
due to a diary conflict 3 Aug 2012

Graham