Atlus has put up a pretty nice site up for FES here, there is a good amount of information, screens, desktops, and even small clips of characters from the original game. Also, some new screens have shown up.
Here is the premise of FES
FES, in addition to adding a great deal of content (both game play and storyline-related) to the main game, includes a continuation of the story entitled Episode Aegis, totaling for an extra thirty hours of game time. When starting a new game, the player is prompted to select Episode Yourself or the aforementioned Episode Aegis. Episode Yourself is the original game with added quests and events, whereas Episode Aegis can be considered a sequel, featuring Aegis as the main character, and the true ending. FES also contains extra costumes and a new weapon synthesis system, twenty-three more Persona, and a “hard” difficulty setting (the original Persona 3 came available with only Easy and Normal modes).
What I don’t understand, with Episode Yourself, do I have to start all over again? Or can I do the new stuff in my nearly completed game?