The CLOUD Message scans have already surfaced on the internet a day before the books official release. It contains nine Final Fantasy XIII Compilation scans including "Creators Messages" for all three of the games as well as what looks like a drawing board showing character artwork, environment designs and even a world map. So out of this what's new?

Final Fantasy XIII
Well we can confirm a very blurry new character for Final Fantasy XIII which I assume has been intentionally blurred as everything else is clear.
Someone has drawn a character doing 99999 damage which possibly confirms they intend the game to break the damage limit.
A new picture of Cocoon can be seen as well as a new area we haven't seen before,.

Final Fantasy Versus XIII
Gameplay! Actual gameplay. It's very small but I don't think anyone can dispute what it is. There are a few images showing Noctis playing through several areas. One image shows him in an area with two clones of himself. I assume that's just for development.
There are lots of new environments to which range from the cities to mountainous plains.

Final Fantasy Agito XIII
A full view of the world map can be seen.
Chocobos are confirmed and they look like their counterparts in Final Fantasy X.
Artwork of walking tanks reminiscent of Final Fantasy VI can be seen in the top right.
The artwork for a new character is also in the bottom right partly covered by some strange symbols.
Lastly some more new environments can be seen in two images.



Source: ameblo.jp