We get a glimpse of a handful of new Pokemon in the trailer.

Litleo: A fire/normal Lion Cub pokemon.

Quick Fix: Pokemon XY Trailer 4S

Flabébé: A new fairy that lives on flowers of different colors(what the site says, but only red in pics so far.)

Quick Fix: Pokemon XY Trailer 4S

As well as a glimpse into our first full evolutionary chain.

Scatterbug -> Spewpa -> Vivilion

Quick Fix: Pokemon XY Trailer 4S

You can also read some in depth info about your entororage of friends at the Pokemon XY website.