Professor Layton vs Phoenix Wright: Ace Attorney will be getting plenty of free additional content according to Nintendo UK, ensuring players have plenty to do even after the main story is completed.

Each week up to the start of September, there will be new content to unlock in-game, either as a Special Episode or a Special Gallery. Episodes take place after the main game story and include new puzzles, while Galleries feature all manner of art with comments from the developers. There will even be some illustrations of Professor Layton and Phoenix Wright drawn in their counterparts' artstyle.

To access said content, select "Extra Content" from the main menu once you beat the game, load your finished game save, then tap "Unlock Content' to unlock the latest addition. These updates will be pushed down periodically.

I'm assuming this same content will be available to North American players, whenever we actually get the game.