Before we go any further, know that the full details on this are a little scarce, and we imagine we'll only get the whole story at TGS next week (or during the Nintendo presser in a few hours). But the latest issue of Famitsu says that upcoming Square Enix RPG Final Fantasy Crystal Chronicles: Echoes of Time will be playable on both the Wii and DS. Same game, available on both systems. Meaning that the Wii version is - yes - essentially a port of a DS game. There's some other stuff about being able to play cross-platform (which is presumably the whole point of this), ala Crystal Chronicles, but again, we'll hold off on getting too excited until we get the full details from Square Enix next week.
[Famitsu, via Game|Life]