I've started to collect a list of sources in Japan for news and information regarding the situation. I will update it regularly.
japantimes - The Japan Times: News and features from the most widely read English-language newspaper in Japan
jt_kamiya - Setsuko Kamiya: Reporter at The Japan Times.
jt_nakata - Hiroko Nakata: The Japan Times staff writer/editor.
reijiyoshida_JT - Reiji Yoshida: Staff writer/editor at The Japan Times : politics, biz, general news.
kzinagata - kazuaki nagata: Reporter at The Japan Times.
JPN_PMO - This is the official English twitter account of Prime Minister’s Office of Japan.
norishikata - Noriyuki SHIKATA: Deputy Cabinet Secretary for Public Relations, Director of Global Communications at Prime Minister's Office of Japan
AmbassadorRoos - John V. Roos: John V. Roos and his family arrived in Japan in 2009. These are his impressions, in English and in Japanese, of his experiences as U.S. Ambassador to Japan.
DailyYomiuri - The Daily Yomiuri: News from The Daily Yomiuri, the English-language sister publication of Japan's largest daily newspaper, The Yomiuri Shimbun.
japanobserver - The Japan Observer: Daily Japanese news links selected by Timothy J. Phelan, editor of thejapanobserver.com and Professor of Japanese Studies at Miyagi University, Japan.
HirokoTabuchi - Hiroko Tabuchi: Tokyo-based biz, econ & tech reporter for The New York Times
TomokoHosaka - Tomoko A. Hosaka: Journalizing Japan for The Associated Press - biz, econ, tech, politics, culture.
yurikageyama - Yuri Kageyama: Correspondent for The Associated Press AP Business Writer based in Tokyo AP
sanchanta - Mariko Sanchanta: Deputy bureau chief of the Wall Street Journal in Tokyo.
daiwaka - Daisuke Wakabayashi: I cover the Japanese tech industry for the Wall Street Journal in Tokyo
AkikoFujita - Akiko Fujita: ABC News Reporter in Tokyo
KyungLahCNN - Kyung Lah: CNN Correspondent
martyn_williams - Martyn Williams: Multimedia Ed & Tokyo bureau chief at IDG News Service. Cover Japan for PC World, Macworld etc.
kenmogi - Ken Mogi: The Qualia Journal
survivingnjapan - Ashley: an American living in Shizuoka, Japan
tokyotimes - Lee Chapman: an Englishman living in Tokyo since 1998
gakuranman - Michael Gakuran
Matt_Alt - Matt Alt: Full time writer and translator
TokyoReporter - Tokyo Reporter: News, features, and photography from Tokyo
tokyodiaries - Nick Roberts: Anthropologist/Qual Researcher on sabbatical in Tokyo
TimeOutTokyo - magazine, city guide Japan earthquake live report, News, emergency information, live reaction
Tokyographer - Anthony Tatekawa: Freelance photographer living in Tokyo for several years.