Over the weekend the Pokémon Company announced that testing of the highly anticipated Pokémon GO iOS/Android app will begin testing in the U.S. in the coming months. The apps developer Niantic Labs have added a registration page on their website where you can go to register for a chance to test the application. Sign up here: http://pokemongo.nianticlabs.com/
There are however a few stipulations, they mention that there are going to be rolling resets of the application and none of the progress will be transferred over to the official launch of the game later in 2016. In addition to this, it appears that there will be an NDA included in the terms and conditions, as you are not allowed to speak about the game.
They note that while the application will be fully functional, and that in game purchases are going to be available, the app will still be in beta, and that there will be portions which you are unable to access.
Pokémon Go releases sometime in 2016 for Android and iOS devices.