Itadaki is a Japanese language toolset for OpenOffice. It offers features intended for students and translators, including furigana (reading) annotation for Japanese text and an integrated dictionary.
OOo writer 3.3.0 (Oracle) on Fedora LXDE. Totally great add-on to remember the reading of new Kanji. Unfortunately the project is not maintained anymore, I use the latest svn packages available on http://code.google.com/p/itadaki/