Pokémon Bank trailer explains the process
The Pokémon Bank, which was announced for a December 27 launch back in October, has a new video available showing you all sorts of Poké stuff. When you download the Pokémon Bank, it allows for the deposit, withdrawl and managing of up to 3,000 Pokémon in private boxes. Like a bank. You can transfer from multiple physical and digital copies of Pokémon X & Y, as well as Black & White, Black & White 2, using the Poké Transporter, a linked application received when you download Pokémon Bank. Remeber, download before January 31 and you will get a free 30-day trial. After that it will run you $4.99/£4.49/€4.99 per year.