According to early info out of Famitsu magazine (reported by Siliconera),Professor Layton vs. Ace Attorney will be out in Japan on November 29, allowing Japanese gamers – and those outside of Japan with sufficient language skills and Japanese 3DS systems – to spend the holiday season solving puzzles and finding contradictions, while the rest of us seethe in jealousy.
There has still been no announcement of a localized version for the West. Every Professor Layton game to be released on DS and 3DS has made it to the West so far (or is on the way), but the same has not been true for Ace Attorney.