That said, there are some official Pokemon-related apps available for download on the App Store and Google Play! These apps are not full-fledged games, but if you're a PokeFan, you should still get some use out of them. Try:
These counterfeit Pokemon games rarely provide what they advertise. Buyers typically wind up with an image gallery, or with a bugged title that crashes upon loading.
Nintendo is extremely protective of its franchises. If news broke about a planned (official) Pokemon adventure on the iPhone or any smartphone, it would create quite a ruckus. And, needless to say, I'd write about it on this Guidesite!
In the meantime, if you're not sure about the legitimacy of any game on the App Store or the Android Market, always take a look at the user reviews. They can usually help clue you in as to whether or not a game is genuine. As a rule of thumb, though, if a Pokemon game is being sold on a digital market that doesn't belong to Nintendo (like the Nintendo 3DS eShop, the DSi Shop, or the Wii Shop Channel), it's not the real deal. Worse, you'll wind up paying for a piece of software that doesn't deliver what it promises.