Cling tenaciously to your Pokémon cards, because this may come as a shock. Nintendo has launched a paid iOS app. The game is Pokédex, a DS title that was originally released in Japan and serves as an encyclopedia of Pokémon characters.
As Ars Technica notes, don't read too much into this release. A "glorified wikipedia" of Pokémon characters is one thing, and a full-on game is another. The franchise still sells very well on the DS, so players eager to catch 'em all won't be able to do so with their iPhones just yet.