The system that it is on has yet to be disclosed; I suggest you check your facts. Also, as this game is unreleased, it belongs in the Final Fantasy XIII and Beyond section.
http://www.jeux-france.com/news18500_square-enix-anime-le-jump-festa.html
http://nenryoubbs.blog.shinobi.jp/Entry/343/ (Shinobi has revealed many games early as well including the recent FFXII:RW and FFT PSP)
I doubt any big site will confirm it until there is some form of media on the title or a PR from S-E.
Once again, all accurate sources covering the jump fiesta say that FFTA2 has not been announced for any system. There is a 99% chance it will be on the DS (because unless i’m mistaken, the ‘A2’ is a reference to Final Fantasy Tactics Advance, indicating it will be a sequel to that title), but until Square Enix announces it, it is not fact.
http://www.watch.impress.co.jp/game/docs/20061218/ffta.htm
If you still don’t believe me then I suppose I’m barking up the wrong tree as you won’t be convinced otherwise until S-E issues a PR them-selves.
Also: Final Fantasy Tactics Advance was my favourite GBA game. I can’t wait for this! Unfortunately, the article said it hasn’t even begun production, so it probably won’t see an English release until late 2008 🙁