Woah!! This is actually the first shocking announcement out of Japan in awhile. A real coup for Sony too imo, this may actually end up as PS3's 2nd million seller!
For people wondering if this is a DS port, it's actually the other way around... when Ninokuni was first unveiled (at that time for DS and "tba console") at L5's mediavision event in 2008, Hino revealed the game had started as a console title, but Level-5 put that on hold and decided they needed to do a DS version too and get that version up to speed. Kinda surprising to find out it was a PS3 game though, everyone assumed it had been a Wii title due to the spellcasting interface and the handheld version going to DS.
Another thing to keep in mind, this is one PS3 that definitely won't go 360 multiplatform, as Hino more or less hates MS after TFLO was canned. I honestly don't think we'll ever see Level-5 make games for an Xbox console...