Microsoft has already announced the availablity of Zune HD & Zune 4.0, but some of the features are not available for users outside US and Canada. With the help of this registry hack, non-US/CA users will be able to enable these features:
Open regedit and navigate to HKCU\Software\Microsoft\Zune and create a key called FeaturesOverride. Within this key, create a DWORD for each feature you want to enable and set its value to 1.
A list of tweakables follow.
SignInAvailable (allows restricted locales to sign in!)
Alternatively, you can also apply this registry fix created by Rafael and apply it.
More at Within Windows.