It was announced today on
the official Minna no Pokémon Bokujō (My Pokémon Ranch) website that a Pocket Monsters Platinum compatibility update will be available by the end of the year. No set release date was announced.
Those that have the game already will be able to download the update for free when it's available. Those that don't own the current version will be able to download the updated version as well for 1000 Wii point.