For those non-US residents, looking to use a Google Voice invite, this is a a windows program that will mask your ip to show you as being in the US. This will allow you to sign up. However, if you have an existing Google Account, you should either change your settings in that account to show you as being in the US, or just sign up for a new Google Account to use with your GV invite.
I haven't used the program myself but I've heard its easy to use and has no malware... Use at your own risk though.
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