A downloadable demo for Zelda: Phantom Hourglass will be available for Japan nine days prior to the actual game's Japanese release date- the demo is available on the 14th of this month.
New scans reveal several details about the game: return of the Grappling Hook, customizable ship, return of the Gorons, new races, fishing & more interactive treasure hunting, and the return of old characters like boat shop owner Beedle and less-than-enthusiastic game host Salvatore.
Finally check out these Japanese commercials for the game: Commercial 1, Commercial 2