These are for the North American server only. I think the North American server is also used for South America and Australia/Oceania. In any case, they should work if your Battle.net account is registered on the US site.
If you want one, go to us.battle.net, log into your account (or create one if you don't have one), and redeem one of the following codes:
Post here afterwards so other people don't try to redeem a code that's already been taken.