Nintendo has added some new details on the upcoming DS title Fire Emblem: Shin Monshou no Nazo Hikari to Kage no Eiyuu. It's a remake of Book II in FE: Monshou no Nazo, or FE3. The translated name of this new DS title is Fire Emblem: Heroes of Light and Shadow. The official website still has some links grayed out, so expect more updates before the game is released.
The release date seems to be July 15 2010.
You'll be able to create your own custom character sometime during the game. Your hero is the 'hero of shadow' referred to in the title of the game. Your hero will get their own prologue and side story missions with new maps.
Graphics seem to be the same as Fire Emblem: Shadow Dragon.
4 Difficulty modes from Normal, Hard, Maniac, and Lunatic.
2 Game modes, Casual and Classic. In casual mode you keep your allies if they fall in battle.
In game plot and character encyclopedia.
The Wi-Fi shop is returning. This is bad for the legitimacy of the games difficulty, and it's just a gimmicky use of Wi-Fi. It's easy to go online and buy overpowered items that are rare in the actual game.
The re-classing system is back.
It looks like Nintendo is following the principle of appealing to gamers of most skill levels which is good. Unfortunately the Wi-Fi shop kind of ruins the chance of the game being legitimate in difficulty.
More info at Serenes Forest.