The first Pokémon Global Link tournament to allow Pokémon from the Kalos region happens next month, on Thursday, February 20 at 4:00pm Pacific. Registration details for this Beta Competition will be available at the Pokémon Global Link beginning January 31 but in the mean time, you'll want to register your copy of Pokémon X or Y with the PGL.
According to the announcement, some players are already qualified for the the tournament based on their performance in the Global Showdown. I've always been into Pokémon for the catch-'em-all aspect and never the competitive scene, but that's not to say I'm disinterested in seeing how players make use of the new generation. Quite the opposite.