Unlike prior Pokémon games, Pokémon X and Y do not innately include Pokémon transfer functionality. Instead, players will need to download an eShop app known as the Pokémon Bank. This Bank functions not unlike the Pokémon Box released alongside Pokémon Ruby/Sapphire, as it serves as a repository for Pokémon, but also allows players to transfer their 'mon between generations of Nintendo's handheld franchise.
Information on Pokémon Bank can be found at the app's official site, but the most crucial detail to remember is that Pokémon Bank is not a free app. Players will be granted a gratis trial period, but once that expires Pokémon fans will need to shell out $5 per year to continue using Pokémon Bank.
While the wait and pricing information is disheartening, it does offer an excuse to read our newly-published Pokémon X/Y review which describes the game as "hands-down the best in the series."