Pocket Monsters SPECIAL Volume 31 has been announced on Shogakukan's website. The next volume is scheduled to be released on
March 27th, 2009. The volume will go on sale for 460yen and its ISBN is 9784091407993. Volume 31 is written by Hidenori Kusaka (日下秀憲) and illustrated by Satoshi Yamamoto (山本サトシ).
Source:
http://skygarden.shogakukan.co.jp/skygarden/