Apple has quietly added TV show purchases on the Apple TV 2 for in Canada, the UK and Australia, and they also added buying options to the existing iTunes rentals.
Before the update Apple TVs outside of the US had only been able to stream TV show rentals bought through iTunes but now people in Canada, the UK and Australia are reporting those limitations have been removed. However, due to the limited storage of the Apple TV 2 you will still stream the purchased TV shows over Wi-Fi, they will not actually be stored on your device.
This is basically an iCloud type feature that allows users to access previously purchased shows and stream them to your Apple TV.
Apple did not make an announcement about the new feature but quietly made it available as it has already been in the US.