Pocket Monsters Diamond and Pearl voice actor Tomoko Kawakami (川上倫子) died on June 9th, 2011 of ovarian cancer. She had been sick for quite a while and unfortunately she was unable to recover. She was most known for her roles as: Hikari's Mimirol (ヒカリのミミロル), Momoan (モモアン) and the Zukan (ポケモン図鑑) in DP1 to 100. She was 41.

Source: http://baobab.dreamlog.jp/archives/4981754.html

Holy sh... No! Tomoko Kawakami was one of my favorite voice actor (especially for her job in AIR), and I'm really sad to learn about her death... especially since she was so young! I was always expecting to see her again in a KEY anime or something.

Actually, I didn't even know she had done some voice acting for the Pokémon series...