Grumble Grumble Grumble
Actually, the correct translation of the series full name ('Agatha Christie no Meitantei Poirot to Marple') is 'Agatha Christie's Great Detectives Poirot and Marple'. This series is currently being shown on the Japanese goverment sponsered TV network NHK, and has not been licensed for US distribution... It's somewhat unusual as very few anime series are based on US literature, but not unheard of. (Miyazaki's "Howl's Moving Castle" is based on a published european children story...)
Official (Japanese) Website...