Here are some links that are good to have bookmarked if you're a CIR, or if you're an ALT doing translation or Japanese study. Please try to keep the most useful links at the top of the list and sometimes-useful links at the bottom. Stars** indicates super useful sites.

Translation

E⇔J

Space ALC (http://www.alc.co.jp/) (how to read the abbreviations/notes on ALC)
Denshi Jisho (http://jisho.org/) and dictionary add-on for Firefox/Chrome
Rikaichan add-on for Firefox/Chrome**
Jim Breen's WWWJDIC
Excite
Weblio
Smartphone apps: Imiwa and Japanese by Renzo

English Reference

Wikipedia**
Dictionary.com**
Thesaurus.com**
English synonym search engine (aimed at Japanese learners)**
English language & usage Stack Exchange forum**
Word and Phrase frequency analyzer**
Linguee E-J translation search engine
Grammar logs Guide to Grammar
Grammarist
All Acronyms
The Punctuation Guide
English forums
Difference between
Tatoeba Example sentence collection
BBC Learning English page
Grammar Girl
English food words (PDF)
Grammar Book- Writing Dates and Times
Good writing guides on San Jose State University Writing Center website
Multilingual signs and phrases (Japanese, English, Chinese, Korean)


Japanese Reference

Wikipedia (Japanese)**
Japanese numbers, units, verb conjugations, etc.**
Yahoo! Japan
Yahoo!知恵袋
教えてgoo
はてな Q&A
三省堂 Japanese dictionary
Japanese sign guidelines
Space ALC- 擬態語・擬音語
日本辞典- 擬態語・擬音語
書き方.com 手紙の書き方
手紙の書き方
ことわざ all guide
Japanese Law Translation
食感 E-J
Glossary of Japanese Buddhism on Wikipedia
JAANUS Japanese Architecture & Art History
kikarui 日本工業規格の簡易閲覧
JAAF陸上競技用語集


Chiba/Japan Reference

ちょっと便利帳 地名
郵便番号検索
Chiba Prefecture Homepage (English/Japanese/Chinese & Korean)
Chiba Prefectural Government branch names (English/Japanese)--Japanese page is more up-to-date
Ministry of Foreign Affairs(MOFA/外務省) English names
Chiba Convention Bureau (CCB)
ちば国際情報広場
Chiba official Tourism website
CHI-BA+KUN Ambassadors チーバくん大使

Chiba Museums, etc.

Chiba City 中央博物館
Chiba City 美術館
Ichikawa Museum of Science
Boso no Mura
Noda Sekiyado Castle Museum
Katori Otone Museum
Otaki Castle Museum
Katsuura 海の博物館

JET/Wisconsin Reference

JET Programme Homepage
Chiba-Wisconsin Program Homepage
CLAIR News
The CIR Homepage & Forums & new forums (after April 2015)
I think I'm lost unofficial JET forums

Other

CIA World Factbook

(Japanese study resources)