Rejoice! The third Professor Layton title will be launching in Europe October 22nd. The title will be launching under the name Professor Layton and the Lost Future.
The North American release is set for September 20th, a month earlier. The title is actually under a different title as well: Professor Layton and the Unwound Future.
Two more games in the franchise remain on the Nintendo DS, while the sixth title will be launching on Nintendo 3DS.