Fans of Pokémon X and Y are now able to download the Pokémon Bank app on their Nintendo 3DS. Originally announced late last year, the Pokémon Bank allows users to store their Pokémon online using cloud storage technology.
Players can try the service for 30 days free before having to pay a fee to keep the storage. This offer will continue until March 14. Also, if you start using it now, you'll get a free Celebi for your efforts (so what have you got to lose).
Pokémon X and Y came out last October. You can read CGM's full written review of the games here.