• Fairy will be a new type. It is weak to Poison and Steel weird, immune to Dragon whoa, super effective against Dragon, Dark, and Fighting, and Fire why and
• Psychic-type Pokemon take half damage from it.
• Sylveon is Fairy-type i think it will be ghost. Some older Pokemon will be reclassified to Fairy, such as Mawile (Steel/Fairy).
• Mewtwo has two new formes, not just one. Both are activated via items. Cool
• The professor's English name is Patrice. Should be a tree like the others
• The Starter final evolutions are Fire/Psychic awesome, Grass/Fighting, and Water/Dark.
• The first Gym is Bug, the second is Fairy, and the fourth is Fighting.
• A few attacks will be dual-typed. Nice
• There will be a new type of battling style that Flying-type Pokemon and Pokemon with Levitate can participate in.
• You will be able to see a Pokemon's EVs at a certain in-game facility. You will be able to boost the EVs through mini-games. It will take about two hours to get one stat to max EVs. Convenient 

Then this morning, CoroCoro finally gave us the first major X and Y details since the games were first announced. Among those details was one tiny little tidbit that the source had first told me about in February - that there would be a new Electric move that drains its opponent's HP. This was the only attack that the person had told me about in February, and yet it is such a specific detail to make up. For that information to be verified three months later seems to indicate that the source is the real deal (unless they are just really good at guessing).
I want to emphasize that under the worst case scenario, I am still somehow, some way, being duped. It would not be the first time to tell you the truth, and all Pokemon webmasters have fallen for fake news before. Thus, I want everyone to take this news with a grain of salt until it is actually verified by Pokemon. If it is verified, then yay, we will be able to post other news this source has sent us since February and up until today. What you will see below is a sampling of some of the news the source has sent since February.
TL;DR - The source seems to be genuine, but still take the information below with a grain of salt. We are classifying it as unconfirmed. Do not soil our beach sand with red liquid if it turns out to be fake. :p

• Fairy will be a new type. It is weak to Poison and Steel, immune to Dragon, super effective against Dragon, Dark, and Fighting, and Fire and
• Psychic-type Pokemon take half damage from it.
• Sylveon is Fairy-type. Some older Pokemon will be reclassified to Fairy, such as Mawile (Steel/Fairy).
• Mewtwo has two new formes, not just one. Both are activated via items.
• The professor's English name is Patrice.
• The Starter final evolutions are Fire/Psychic, Grass/Fighting, and Water/Dark.
• The first Gym is Bug, the second is Fairy, and the fourth is Fighting.
• A few attacks will be dual-typed.
• There will be a new type of battling style that Flying-type Pokemon and Pokemon with Levitate can participate in.
• You will be able to see a Pokemon's EVs at a certain in-game facility. You will be able to boost the EVs through mini-games. It will take about two hours to get one stat to max EVs.

source: gaf