Japanese gamers can learn English with their DS. There's even a Japanese-English dictionary for the system. Now it's time for us poor monoglot anglophones to expand our linguistic horizons. A coder known as Zoelen has just released an early version of Project JDS. The app teaches you to recognize and write both hiragana and katakana characters, even listen to their pronunciation. And if you're really nice, you can use the touch screen to draw characters and get berated for using the wrong stroke order!
It isn't much to look at, but it gets the job done and is surprisingly feature-rich for a homemade app. Now if only it had a catchy name. Something like ... Touch Dic.