A new trailer for Animal Crossing 3DS has been released yesterday along with new information for the game, such as Tortimer will no longer be the mayor, instead you will be the mayor and direct town activities.
The game will also include new villagers, like a deer, and old ones will be returning with more and new personalities. All shops will also be at the mall that is outside of your main town.
Animal Crossing 3DS will be out this Fall in Japan and early 2013 in Europe. A North American release date has not been given yet.
I think that the game will arrive in the us late mid 2013 or early mid 2013.