Japan received an official iOS app last month and now the US and Europe can download the official app for $1.99/£1.49 GBP.  Here’s the official press release:

POKÉMON LAUNCHES OFFICIAL POKÉDEX APP FOR iPHONE, iPAD, iPAD MINI, and iPOD TOUCH
Access Official Data and Images for More than 640 Pokémon At The Touch of a Button with the Pokédex for iOS Application!
LONDON, UK—December 10, 2012— The Pokémon Company International announced today that the official Pokédex application, an illustrated encyclopedia of more than 640 Pokémon characters, has arrived for the iPhone, iPad, iPad mini, and iPod touch[1], providing fans in North America and Europe[2] with a new and extremely helpful way to access comprehensive data about their favourite Pokémon. Fans can now download Pokédex for iOS from the Apple App Store and take an in-depth look into the world of Pokémon straight from their iOS device.

The wide range of data in the Pokédex for iOS application is conveniently accessible for each Pokémon character, giving fans invaluable information such as how to evolve a Pokémon, locations where specific Pokémon are found, and which types of attacks an individual Pokémon is weak against. The Pokédex for iOS is a must-have companion when playing Pokémon video games, including the recently launched Pokémon Black 2 and Pokémon White 2.

After downloading the official Pokédex for iOS [£1.49 GBP], fans have immediate access to the Unova Pokédex (National Pokédex No. 494–647) and can quickly browse Pokémon either by name or by Pokédex number, move, Ability, or type. The application’s intuitive interface allows users to sort Pokémon in numerous ways based on their distinctive characteristics. Once a user chooses a particular Pokémon, a detailed and dynamic 360-degree image of the Pokémon appears with a full encyclopedia entry, including its name, height and weight, type, Ability, and moves it can learn. Each Pokémon’s entry includes the locations where the Pokémon can be found in Pokémon BlackPokémon WhitePokémon Black 2, andPokémon White 2.

Once fans get Pokédex for iOS, they can search the app’s Store to purchase the full National Pokédex, region by region: Kanto Pokédex (National Pokédex No. 001–151), Johto Pokédex (National Pokédex No. 152–251), Hoenn Pokédex (National Pokédex No. 252–386), and Sinnoh Pokédex (National Pokédex No. 387–493) for £3.99 GBP each. Every regional Pokédex features the same level of detailed information as that provided by the Unova Pokédex.

[1] Pokédex for iOS compatible devices include: iPhone 3GS, iPhone 4, iPhone 4S, iPhone 5, iPod touch (4th and 5th generations), iPad 2, iPad (3rd and 4thgenerations), and iPad mini. Pokédex for iOS is compatible from iOS 6.0. An update is necessary for devices with an OS earlier than 6.0.
[1] Pokédex for iOS is available to download from the Apple App Store in the following countries: Austria, Belgium, Canada, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, United Kingdom, United States of America

Pokédex for iOS can be switched from English to French, Italian, Japanese, German, and Spanish. For information about the Pokédex for iOS application, please visit www.pokemon.co.uk/pokedexios.