This must've JUST hit, I looked around and apparently it's on a Japanese Gaming blog:
http://blog.livedoor.jp/odeko_06/archives/50672010.html
And IIRC, this is the same reliable source which told of FFXII:RW and the Chocobo DS game among others.
If that's the case, OMFG!
And plus it seems to say it could be either DS or PSP, the NEW game seems to be called FFT Advance 2 (?) while a remake of a PS1 game on PSP would make sense.
EDIT: The Link actually gives me an old blog from September, which I think talks about Revenant Wings (from Babelfish). I'm sure someone could clear it up, this IS that reliable news site for certain Square-Enix things.
EDIT 2: This could be some kind of surprise game for Jump Festa which is later this week.
EDIT 3: Well found this link (in French) but it's just an FF fansite I've never heard of before.
http://ffworld.com/?rub=news&page=voir&id=590
They don't divulge the source, just a PSP remake of FFT with an Onion Knight Job and an FFT-A sequel for an unknown platform.