From Bulbapedia, the community-driven Pokémon encyclopedia.
Ash & Pikachu (Japanese: サトシとピカチュウ Satoshi and Pikachu) is a manga based directly on the Johto and some of the Hoenn seasons of the anime. It is created by Takashi Teshirogi.
All six volumes of the manga was translated into English by Chuang Yi in Singapore.
Differences between the anime and the manga
This manga, while not having striking differences like The Electric Tale of Pikachu, does put a few twists on certain episodes of the anime by retelling it in a fun way. For example, the second chapter of the first volume combines the Pokémon fortune-telling episode and Ash's match against Whitney, but with a couple of changes.