The free-to-play game uses your phone's camera and GPS to populate the world around you with Pokemon. As you walk around, you can discover more of the creatures, battle other Pokemon trainers, fight for control of Pokemon Gym locations and, of course, catch 'em all.
Enterprising Pokemaniacs in Australia and New Zealand got a head start, downloading the game on iOS and Android yesterday. North America got its release Wednesday evening. (If you're having trouble finding it, try searching for "Niantic" instead of "Pokemon").
Niantic, an ex-Google startup, previously worked on a similar map-based, GPS-powered game called Ingress. Pokemon Go is Nintendo's second foray into smartphone games, having launched the Miitomo social app earlier this year.
Update, 6:04 p.m. PT: Pokemon Go has now launched in North America.