In the Union Kingdom Hearts Realm they have an article about it!

The latest issue of the Japanese magazine V-JUMP has published two screenshots & information regarding the upcoming Kingdom Hearts 2: Final Mix. Although not much information was given about the game, it will feature English dubbed voices, plus a whole variety of new content (e.g. cutscenes).

Features Speculation:
New Secret Movie? (Ref: 1ST Screenshot)
 KH: CoM 3D Minigame? (Ref: 2ND Screenshot)
 Possibility of Mushroom Heartless (Ref: KH2 Ultimania)
 Possibility of KH:CoM Org. Member Battles (Ref: KH2 Ultimania & 1ST Screenshot)
 Possible Reveal of Zexions Weapon (Ref: KH2 Ultimania)
 Possible Reveal of Mickey's Letter Contents (Ref: KH2 Ultimania)

http://www.gamespot.com/pages/unions/read_article.php?topic_id=24979880&union_id=256

HARDCORE KH FANS LIKE ME, WELCOME TO OUR SANCTUARY!!! I LOVE YOU SQUARE-ENIX!!!!!!!!! :D