From Bulbapedia, the community-driven Pokémon encyclopedia.
A chapter is the Pokémon Adventures equivalent of the anime's seasons. They divide the manga into sections, which have a separate plot, though the characters and events from one chapter may be used in another, later chapter. Each chapter is named after a main series game, and the characters introduced in each chapter generally share those names.
Chapters are further broken down into volumes, which are then separated into rounds. There is no definitive number of rounds in each chapter.
Ten chapters have been released, of which first eight have been fully translated into English and published by Chuang Yi.
VIZ Media has fully translated and published the first three chapters and for now the company is planning to release the chapters between Gold, Silver & Crystal and Diamond & Pearl starting from March 2013 with the release of Volume 15. In addition, they are currently translating Diamond & Pearl chapter and Black & White chapter as second and third series.
List of chapters