Note that this only applies to publishers getting ready. Google won't actually sell ebooks outside of the US just yet. An Australian tried to buy an ebook and he could not.
I wouldn't get to excited just yet; remember, Google had the publisher support pages open to the public months and months before the Google eBookstore launched in December of 2010. They're just as likely to hold the international expansion for a few months just to make sure content is available.
Does anyone know when those options first appeared?
Edit: Couldn someone in the UK, CA, or AUS try to download the Google eBooks apps for Android or iOS? I want to know if you succeed. If the apps are live already then the expansion should happen soon.