References
Japanese-English; English-Japanese Dictionary
Compiled by Seigo Nakao
Published by Random House
ISBN#: 0-679-78001-7
*You can look up words in both Japanese and English. For the Japanese-English section, words are arranged in alphabetical order by romaji. Kanji, hiragana, and katakana are provided along with the most common English translations. This is a very good dictionary if you are just starting to learn Japanese.
A Dictionary of Basic Japanese Grammar
By Seiichi Makino & Michio Tsutsui
Published by The Japan Times
ISBN# 4-7890-0454-6
* A must have dictionary explaining the most common and basic grammar, including particle usage. Grammar phrases/particles are arranged in alphabetical order by romaji. Detailed explanations and examples are given in English. Intermediate and Advanced Grammar versions are also available.
The Kodansha Kanji Learner's Dictionary
Edited by Jack Halpern
Published by Kodansha
ISBN#: 4-7700-2855-5
* An excellent dictionary for beginner and intermediate kanji learners. Teaches how to break down kanji into strokes and radicals. Kanji is arranged into 4 basic patterns (left-right, up-down, enclosed, solid) then broken down by radical and stroke order. An index at the back also includes all the kanji broken down to its hiragana meanings, arranged in alphabetical order by romaji. Each kanji entry includes english meaning, stroke order, and most common words (of course with their English meaning) associated with it. Do be careful though as some of the words are now a bit archaic.
Complete Master's Series: Level 3: The Japanese Language Proficiency Test: Grammar Excercises
ISBN#: 978-4-88319-354-7
* The MUST HAVE book for those studying for the Level 3 JLPT. There are many books out there, but I found this one to be the most helpful. Provides all the grammar points for both level 4 and level 3 that will appear on the test, along with a quick English explanation. Grammar points are arranged by plain, past, etc. forms. Basic Keigo (polite/humble form) and Passive/Passive Causative is also included. Examples sentences are given, followed by practice excercises and pratice tests. An index at the back includes all the grammar points in arranged in Japanese hiragana order (ie. あ、い、う、え、お). Most 三級 books are written entirely in Japanese with Japanese explanations of grammar points. This one at least offers a bit of English. Books for 四級、二級、一級 are also available in this series. It should also be noted that the JLPT 4 is the easiest level and JLPT 1 is the hardest.
(Edit 2010: Starting from 2010 there is a new leveling system for the JLPT. This book was primarily for studying the old level 3 --which is harder than the current level 4 but easier than the current level 3. The reorganizing was primarily because people claimed the gap between the old JLPT 3 and 2 was too difficult... and as someone studying for JLPT 2, I can attest to this.)
Nintendo DS + Kanji Sono Mama Dictionary
ISBN#:
* If you're looking for an electronic dictionary, just buy a DS. Seriously. This "game" costs only 4600 yen (roughly $40 with the exchange rate). You can look up words in both Hiragana or English. Yellow words offer the most common English meanings along with example sentences. Red words offer only Japanese explanations but will probably direct you to synomnyms or related words that are bound to have English translations. The best part of this game is the ability to look up kanji by WRITING IT IN. That's right, using your stylus, you can sketch out the kanji and the game will find the best match for you. You can input up to two kanji in succession (for compound words). The downside is the game is sensative to stroke order so you should have a basic understanding of how kanji is written. The word database is a bit limited compared to more expensive electronic dictionaries but overall I have found it to fit my needs.
Jim Breen's WWWJDIC
http://www.csse.monash.edu.au/~jwb/cgi-bin/wwwjdic.cgi?1C
* This is a somewhat controversial dictionary site (many claim it doesn't give correct translations, particularly based on context) but I still consider this my favorite online dictionary. Not only is there the normal word input, there is also a "translate" text section. This is different from Babelfish in that it will identify the words and give a word-by-word translation. It also has the ability to recognize simple conjugation patterns. Each entry also links to a list of sample sentences. (I would also like to suggest that you NEVER use Babelfish! It does not translate anything correctly. I can tell when my students cheat and use it, hence my personal vendetta against it ^^;;).
Tanos: JLPT Grammar List
* This site lists all the grammar and their english translations (along with sample sentences, most of which are taken directly from the master's book) for all of the JLPTs. This should be used in conjuction with the one of the JLPT Master Level books I mentioned above. It is particularly useful if used for 二級 or above, as 二級 study books are almost all in Japanese. Even if you aren't studying for the JLPT it's still a great resource for those difficult grammar points.
(Edit 2010: This site has now been reorganized for the new JLPT leveling system.)