Wikipedia also had something to say about it
http://en.wikipedia.org/wiki/Final_Fantasy_IV_%28Nintendo_DS%29
According to executive producer Takashi Tokita, the scenario writer and lead game designer of the original release, 3/4 of the original script had been left out from Super Famicom original release, but this lost material will be reworked into the remake, while some new events will also be added. The player will have the possibility to use the Nintendo DS stylus to move around similarly to the Final Fantasy III remake, while some minigames will require this usage of the stylus. Additionally, the developers are currently working on a feature which should add replayability to the game, although it will not necessarily be a New Game Plus feature.
In June 2007, Square Enix will hold a casting for a vocalist to sing a version of Final Fantasy IV's "Theme of Love" rearranged by Nobuo Uematsu.
