This game contains 4 mini-games. They can be used to train both your Katakana & Hiragana.
It also has a mode for training your vocabulary in both Romaji and Kana. By default it comes preloaded with a few hundred words but you can add/modify your own words and images.
SVN Browse:
http://japanesekana.svn.sourceforge.net/
VS2010 SVN:
https://japanesekana.svn.sourceforge.net/svnroot/japanesekana