Some info from the official Atlus website, plus a trailer:
Official Site: ペルソナ公式サイト
Trailer: PSP版『ペルソナ』PVを先行公開 - ファミ通.com
- All the original FMVs will be remade by Kamikaze Douga, and there will be many brand new FMVs as well to enhance the storytelling.
- Shoji Meguro will be arranging all the original BGM and the vocal tracks will feature Yumi Kawamura, the vocalist for the Persona 3 tracks.
- The interface has been fully revamped to take advantage of the full widescreen view for the benefit of all users.
- Both the original scenario and the Snow Queen scenario will contain additional dungeon floors not found in the original. The new dungeon elements will also contain tricky puzzles and extra content for the player to unravel.
- The game has been fully rebalanced to enhance the playing experience from the original version. The encounter rate and dungeon designs have been tweaked as well. There will also be multiple difficulty settings to more player choice.
- Battle animations can now be skipped entirely, and the battle load times have been decreased to 2/3 the rate of the original game.
- There will be many more save points available throughout the game, and for portable fans the game will also feature a quicksave feature.
- A beautiful 2D town map has been created for the game to bring it up to the standard of the rest of the series.