Furuya Tohru (古谷徹) announced on his website that he will be the voice actor for Arti, the Hiun City Gym Leader in the Japanese version of Pocket Monsters Best Wishes. Furuya Tohru is one of the biggest names in the Japanese voice acting arena, having played major roles in some of the most popular anime ever made. This will be his second role in the Pocket Monsters anime as he played Sorao (ソラオ) in the first movie.

Furuya is most known for his roles as Amuro Ray in the original Gundam series and its direct sequels, Pegasus Seiya in Saint Seiya, Yamucha in Dragon Ball and of course Mamoru Chiba from Sailor Moon, as well as Kyosuke in Kimagure Orange Road, Hyuma in Kyojin no Hoshi and Ribbons Almark in Gundam 00. He also portrayed the voice of Mario in some early Japanese productions.

He announced that he would be in three of the upcoming episodes of Best Wishes: Yaguruma Forest! Kurumil and Arti!! (ヤグルマの森！クルミルとアーティ！！) airing on January 27thm 2011, Hiun City - Fushide Panic! (ヒウンシティ・フシデパニック！) airing on February 24th, 2011 and Hiun Gym Match, Purehearted Bug Pokémon Battle! (ヒウンジム戦純情ハートの虫ポケモンバトル！) which airs on March 17th, 2011.

Update: Furuya Tohru's website has been update with revised airdates that better fall inline with the currently revealed episodes. The numbers stated are internal production numbers are are skewed by two because of the Hikari and Takeshi specials that aired on February 2nd, 2011.
★【TVアニメ】『ポケットモンスター　ベストウィッシュ　#22～ヒウンシティ・フシデパニック！』2/24（木）予定19：00-19：30/TV東京/アーティ役
★【TVアニメ】『ポケットモンスター　ベストウィッシュ　#25～ヒウンジム戦純情ハートの虫ポケモンバトル！』3/17（木）予定19：00-19：30/TV東京/アーティ役

Source: http://www.torushome.com/topics.html