If you update the Google Voice app, you cannot make phone calls anymore if you cannot randomly validate a US phone number. Which pretty much kills the only use case for googlevoice: having a phone number when traveling, when you cannot receive SMS on your US phone number (thanks verizon).
You can still call from the website, for now, but not the app.
edit: btw the app seems to work fine, until you try to make a call. Then it shows a dialog:
> One last thing... > Before placing a call, you must validate your phone number > [cancel] [validate]
(after removing my us number and adding a international one i can acces, the buttons change to [cancel] [associate a number] despite me having a non-us number)
if i try to associate a non-us number Then I get the dialog:
> Google is not available outside the United States. To use Google Voice, register using a US-based phone number.
(i'm translating those messages from french, so it might be slightly different)