For preordering ToS, you get a lithograph (nice print) of the Tales cast - roughly 9"x14". But as for the art book, it is apparently supposed to come with the game itself. That part is a bit confusing...
I've already preordered it. I could use a good RPG with a fighting system that doesn't get boring. The Tales system works well and is quite fun. It was rated about a 9 in the Japanese version review I saw, too. I'm sold!