JWPce - JWPce is a free Japanese <--> English dictionary and word processor created by Glenn...
Akebi Japanese Dictionary - Offline Japanese-English kanji dictionary.
zkanji - zkanji is a free and open-source study tool and dictionary of the Japanese language.
Jisho - Powerful and easy-to-use online Japanese-English dictionary with words, kanji and example...
Anki - Anki is a program which makes remembering things easy. Because it's a lot more efficient than traditional study methods, you can either greatly decrease your time spent studying, or greatly increase the amount you learn.
Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.