This is some pretty cool news. I had not known that there was an anime series still using cells. Sazae-san is one of the longest running shows ever made. It started in 1969 and is the longest running anime series with a whopping 2,250 episodes!
Anime News Network is reporting that the Sazae-san television anime will be making the change from cels, the transparent sheets on which animation frames are drawn, to digital production in October 2013.
Their report mentions that according to the Association of Japanese Animation, Sazae-san was the only anime left on the air that used hand-drawn cel animation. With the series moving to digital production, there will be no television anime left still using cel animation.