Methods of obtaining it include moving to New Zealand. Now live for our US visitors!
http://www.nintendoworldreport.com/news/42964/pokemon-go-launching-on-app-stores-now-live-in-united-states
Pokémon Go is beginning its worldwide launch for iOS and Android.
iOS users in New Zealand can currently download the application from the local app store, while international users can create a New Zealand app store account for the free app or wait as it moves its way west. The application is showing live on Google Play but shows no eligible devices outside of NZ/Australia - though the .apk (Android app file) is in the wild.
Pokémon Go launched on the US iTunes and Android stores at 9pm Eastern tonight (July 6).