In addition, GHM will release a guide book called "Kurayami Magazine," named after an earlier iteration of the game. It features a long interview with Suda 51 and original character designs.
Both items are listed on the Japanese GHM store website, with the soundtrack available tomorrow and the book on September 9. Neither has been posted on the American store yet, and we're asking-slash-begging Grasshopper for more information.
Update: GHM is selling the soundtrack on its international site now, limited to 1,000 copies. The first 300 will be signed by Akira Yamaoka!