From Bulbapedia, the community-driven Pokémon encyclopedia.
The logo of Poké Transporter
The Poké Transporter (Japanese: ポケムーバー PokéMover) is an application for the Nintendo 3DS line of systems, which will be released on the Nintendo eShop. It will serve as an extension to Pokémon Bank.
This software will allow players of the Generation V main series games to migrate Pokémon to Generation VI games. The service allows one-way transfer of Pokémon from Pokémon Black and White and/or Pokémon Black 2 and White 2 to Pokémon X and Y. When one of the Nintendo DS cartridges is inserted into the system, it will be possible to deposit Pokémon belonging to it on the Pokémon Bank. Then, such choices can be downloaded into a connected Generation VI game using the Nintendo 3DS.