Links

Seattle Japanese Garden - official site,  run by Washington Park Arboretum
Seattle Japanese Garden - official site at Seattle Park and Recreation (city of Seattle)

Kubota Garden - Seattle, WA; 20 acre landscape that blends Japanese garden concepts with native
Northwest plants
Kubota Garden - Essay from HistoryLink
Bloedel Reserve - on Bainbridge Island, contains Japanese Garden
Japanese Garden - article from Wikipedia
Japanese Garden Journal - from Rockport, Maine; a publisher of Sukija Living
Kyoto Gardens - a rich website (includes origins, elements and glossary)  from Bowdoin College, Brunswick, Maine
Types of Japanese Gardens - Rock Gardens, Dry Landscapes, Hill Gardens, Karesansui, Kasam, Tsukiyama, others; a page from Buddhism and Shintoism in Japan
The Japanese Garden Database - a repository of information on the historical and contemporary gardens of Japan as well as the gardens outside Japan that have been inspired by the culture
Japanese Garden Design Principles - collection of informative articles on Japanese gardening, including Bonsai; from Gardening with the Helpful Gardener
Haiku Northwest - local group of haiku poets, meets second thursday of each month (usually Bellevue)
The North American Post -   the oldest Japanese newspaper in the Pacific Northwest. Since 1902, it has been serving Nikkei community.

2 added 9/13/14, courtesy of Koichi Kobayashi - thank you, Koichi!:
Study of Landscape Space and Design Elements at Seattle Japanese Garden, 2014 - PDF download - very instructive paper on principles and essence of Japanese Gardens
Seattle Japanese Garden - digital archive

Added 4/8/11:
Japanese Garden Dictionary - Glossary of Japanese Garden and their history; English and Japanese index
Japan Fact Sheet - Flora and Fauna
Ministry of Foreign Affairs Japan - from foreign policy to culture
Web Japan - ever-evolving site, includes Kids-web-Japan

Links about Japanese Butoh dance:
• Wikipedia on butoh
• Flesh + Blood Mystery Theater
• NYT - Butoh: Dance of Darkness

If you can think about other interesting websites, please share below - i'll add them to the list.