Final Fantasy IV preview at 1-up.
"The first thing Final Fantasy IV fans will notice about its new DS remake are the voices. To be fair, the game features plenty of other new additions that were never seen in its previous incarnations, whether Super NES, PlayStation or Game Boy Advance. The graphics, for instance: FFIV is being developed by the same team at Matrix that crafted last year's DS remake of Final Fantasy III. And like that game, it runs in a fully-3D engine and sports some of the sharpest graphics ever seen on the DS.
But the DS version of IV is as much of a leap over its predecessor as the original game was back in 1991. Clearly, Matrix learned a great deal in the course of reinventing FFIII and has applied those lessons to its sequel. Many of the improvements are small, but they also make the game a better experience. Gameplay, for instance, has been moved to the top screen; the bottom screen is now reserved for a map. Town maps come fully-revealed, but the world and dungeon maps only fill in as you explore the game. Despite the relocated action, the option for stylus-driven control is still present -- dragging a touch pen around the screen will cause your characters to walk or run. And this way, the stylus never obscures the action."
Full Source: 1-up