It's just made its way to the UK and the official Pokémon Twitter noted that it should arrive in the US in just a few hours.
Of course, the Pokémon Trading Card Game has been available online for some time on its official website, but this is The Pokémon Company's first full game on an iOS device. Previously, Pokémon only appeared on mobile platforms for non-gaming apps like that time they invaded Google Maps for April Fools. What a splendid time that was.
The iPad Pokémon Trading Card Game port is compatible the PC and Mac versions of the game, so you can shuffle your collection between devices for that on-the-go Pokémon fix.