It will be possible to move your collected Pokémon from Pokémon Black, Pokémon White and the sequels to the upcoming 3DS titles Pokémon X and Pokémon Y, Nintendo has announced.
Using Poké Transporter it will be possible to move your Pokémon to the a cloud-based Pokémon Bank, which will then allow you to transfer them into the new 3DS games.
Bank will be a downloadable app for 3DS and will require an annual fee, although pricing hasn't been announced. Nintendo has sad there will be a free trial period after the launch of Pokémon Bank.
Pokémon X and Y will be released October 12.
Source: Nintendo Direct