zkanji - zkanji is a free and open-source study tool and dictionary of the Japanese language.
JA Sensei - Complete suite to Learn Japanese !
RomajiDesu - RomajiDesu is a free online bi-directional Japanese-English dictionary, Kanji dictionary, Sentence analyzer and Japanese to Romaji/English translator, and Romaji to Hiragana/Katakana Converters for Japanese learners.
Akebi Japanese Dictionary - Offline Japanese-English kanji dictionary.
JWPce - JWPce is a free Japanese <--> English dictionary and word processor created by Glenn...
JDICT - JDICT is a cost-effective application that provides you an opportunity to convert the Japanese text into English, making you easily communicate with your friends without any disturbance.