To receive calls with the app you'll have to forward calls to google chat in the google voice account (google.com/voice).
Because of this announcement you may need Google credit to make/receive calls outside the US Official Google Blog: Calling from Gmail now in 38 languages, with lower rates to over 150 destinations
So far people we know have been able to use the app without credit outside the US, it may be because their account was created in the US.
First of all - Thanks for a great product!
2nd - all your instructions & support has worked as described!
3rd - not sure if GV credit systems refreshed immediately but tested with my father calling from Vietnam to US & me calling him from US, & it appears no credits were deducted either way.
Will check tomorrow.
Sorry for being a bit unclear with the original question.
But basically it was mobile to mobile call internationally and GIP performed as advertised on both of our EVO's.
Thanks again!