On December 27th, Nintendo and The Pokémon Company will launch Pokémon Bank, a cloud service for Pokémon X and Y that allows you to store up to 3,000 Pokémon, and access them via the Internet whenever you please. This morning, they released a trailer explaining the service, which you can watch above.
As previously reported, Pokémon Bank is a paid service. It will cost $4.99 per-year, and will give you access to 100 storage boxes to store your Pokémon in. Each box will be able to store up to 30 Pokémon. If you download the app before January 31st, 2014, you’ll get a free month-long trial.
When you download the Pokémon Bank app for your 3DS, you’ll also get another app called Poké Transporter, which will allow you to import Pokémon from Pokémon Black/White and Black/White 2 into Pokémon Bank. These Pokémon can then be accessed and transferred to Pokémon X and Pokémon Y.
You can find more details on Pokémon Bank in this FAQ on the Pokémon website.