With the Pokemon Bank, one is able to deposit, store and manage up to 3,000 Pokemon, and this will also include those from previous games. When it is used in combination with the Poke Transporter, one is able to move Pokemon from older generations into Pokemon X/Y. The Pokemon Bank experienced a delay from its targeted December 27 launch date after going through some “service disruptions” on the Wii U and 3DS eShops, and even in its home country of Japan, it was pulled due to similar issues. This particular app might be a free download, but you will need to fork out a $4.99 annual subscription fee in order to make use of its services.
On a side note, have you ever wondered whether Professor Oak is really who he makes out to be, an expert on Pokemon? He has studied them for years and only has three in his Pokedex, which is a shame, really.