Online Resources:

About: Japanese Lessons: Japanese lessons including kanji, hiragana, katakana and grammar (updated weekly).

Apricot Web: This site has some Japanese lessons and vocabulary.

Chiron's Survival Japanese: Has many short dialogues with some audio and grammatical explanations.

Common Terms in Anime (by The Yale Anime Society): This site contains some of the common terms heard in anime and gives their explanations.

Drill and Learn the Japanese Kanji : This site has flashcard tests of the on-yomi, kun-yomi, and meanings of kanji in English or French. You can drill in the Jouyou kanji order or in the Japanese Language Proficiency Test order.

Hans Wadsten's Japanese Page: This site has the kanji characters for the first six grades.  (You will need to be Japanese enabled for this.)

Japanese Online: Contains 16 Japanese lessons. (You will need to be Japanese enabled for some of the later lessons on this one.)

Japanese Page, The (How to Wow in Japanese): This site has some strange vocabulary as well as grammar.

Japanese Writing Tutor, The:Writing instructions for hiragana, katakana, and kanji. 

Jim Breen's Japanese-English Dictionary Server: This site is very useful and has many ways to search for words.  It also does translation.  If you don't have Japanese fonts, use the graphic interface.

Kanji-a-Day: This site has vocabulary and kanji lists for all four levels of the JLPT (Japanese Language Proficiency Test). It will also help you study for the tests by intoroducing one kanji from each level every day.

Kanji Step: This site has good writing lessons and practice proficiency tests.

Names in Japanese: This site has Japanese translations for many names.

Reiko-chan's Japanese for Anime-Lovers: Has several lessons including hiragana and katakana.

Japanese Learning Products:

Language Express: Has items including flashcards and bookmarks.