Asahi.net. This Java app tests your knowledge of onyomi, kunyomi, and meanings. Multiple choice, all 1945 joyou kanji, goes in blocks of 60 or all of them at once. Also pretty good for practicing hiragana.
TV Asahi--has subtitles
TV Asahi's TV guide, so you know what you're looking at
Japanese-English quizzes
This page contains a huge number of quizzes suitable for English speakers who are learning Japanese, or Japanese speakers who are learning English. Quiz yourself on drinks, animals or sports, common nouns, or obscure medical terminology. Very extensive collection, suitable for total beginners or fairly well-progressed students.
Quizlet Japanese Quizzes
Quizlet has a ton of Japanese quizzes and even some games. You can study hiragana, katakana, kanji, basic vocab. Well worth visiting.
Japanesefile, giant lists of words
Japan Times for kids
Green-and-black quizzes
Tae Kim's forum
NHK news
Nakama, learning site
More About.com
How to get the fonts on your computer
Tim's Takamatsu
Let's Learn Japanese! Lots and lots of pirated materials!
Kaeru Modoru
thyis is just a list randomizer
More kanji
A patricular discussion on ageru/kureru
Bad Bento Boxes
Verb Conjugator
Tangorin
Verb conjugation chyart
Radicals (hyas line underneath each)
Radicals (a bit messy)
Art of writing japanese kanji and kana - All for your japanese studies!
Kanjidamage, it looks like the Black Flag logo
Japanese counters for days of the month, objects, people and etc.
All Japanese, All The Time!
Let's Learn Japanese! Children's Books to Horror Flicks, all here The Denshi Jisho Forum, ask questions and read what others have to say.
EUDICT JAPANESE/ENGLISH DICTIONARY