Touch de Nihao is a utility program designed to help Japanese people get around in Chinese (Mandarin, we assume). It features a translation function that translates words written on the screen, as well as subway maps of Shanghai and Beijing.
The screenshots seem to show some sort of lessons, as well, or a dictionary organized by subject. The screen here, with the, uh, thing enjoying a beverage, is titled Nomimono (drinks) -- indicating some kind of subject page.
We probably won't see an English-Chinese version of Touch de Nihao, but we'd like to. We're fans of DS language learning.