Let me clarify: You need a US based cell phone number (last I looked) in order to establish a new GV account. I happen to have a working GV number (US-based) because I had a number back before Google bought Grand Central. GV "works" where ever you happen to be, but the issue you'll have outside of the US is in having a US-based cell phone number to which to create/link your GV account.

Back when the service was GC, you could sign up with a number from any country. When GC became GV, all accounts were migrated over with whatever cell phone data was in your account at the time. Since then, I've moved provinces and no longer have that cell phone number. I cannot change my cell phone number in my settings because GV will only accept a US-based cell phone if you try to change the info that was migrated over. Similarly, to sign up for a new GV number, you (last I checked) need to give them a US-based cell phone number. (And again last I checked, you can only get a US-based GV number.)

You can't use a Skype-In number to sign up for GV (which is also US-only, but at least we can get one without getting a US phone). You can also associate a SIP number with your GV, but you can't sign up for the service with only a SIP number. (I do have a SIP number back from my GC days, and it's associated with my account, but I still cannot change my cell phone number to my current number.)

When Cheyennedonna first recommended pbxes a couple of months ago (?), I tried to sign up from Canada but couldn't. It wanted me to be in the US.

So, I actually do have GV "working" in Canada, but I can't connect it to any phone. And if I didn't already have it from before it became GV, I wouldn't be able to get it now. So, I consider that to be "not working" in Canada if you can't sign up for it. (Even though of course, if you have GV, you can use it from anywhere in the world.)