The official Pokémon movie website has updated. Translations follow:
Media Information
Magazines:
Monday January 15th: "Corocoro Comic" - Presentation of artwork
Saturday January 20th: "Corocoro Ichiban!" - Presentation of artwork
*Note that these are the scheduled publication dates, and as such are subject to change without notice.
Source:
http://www.pokemon-movie.jp/news/?p=3178