Found a great app for android, for folks interested in learning Japanese. This is mainly for learning the Kana (characters). We are starting with Hiragana, as I read that was recommended. It has been a bit slow going with books, but this app has several quiz options, a great chart, actually the best I've seen that shows the PATTERNS of the hiragana characters as they relate to each other sound-wise, etc.
kana, fyi,

VERY very helpful. There is even a 'beta' quiz that tests one's drawing of the characters. Excellent. (drawing recognition)
Here is a link with description. I think it should be available for kindle fire, android phones and other android tablets. Possibly it is available for other operating systems also.