The Ultimania series are guide books published in Japan solely for Square Enix RPGs, with 38 releases so far, beginning with Final Fantasy VIII in 1999. Anyways, apart from scenario guides and walkthroughs, these books also contain interviews with the development staff of the games.
So the Ultimania guide book for Kingdom Hearts: Birth by Sleep (on PSP) will be going on sale in Japan today. The FF Reunion fansite already got their hands on the Ultimania guide and condensed some points from a Tetsuya Nomura interview regarding Kingdom Hearts 3. Nomura said that there are two Kingdom Hearts games currently being made, none of which is Kingdom Hearts 3. He said that the development of KH3 is dependant on Final Fantasy Versus XIII, as the entire staff is busy working on the latter title once Final Fantasy XIII was finished last year.