Escape Artist http://www.escapeartist.com/japan/japan5.htm
Job listings from ESL to management and high tech.
Business Opportunities with Japan according to JETRO (Japan External Trade Organization) http://www.jetro.org/
Has information on conferences, a guide to JETRO in the U.S.A., and Practical Information on Doing Business in Japan. In English.
Headhunter Japan http://www.headhunter.jp/
Online recruiting site for executive searches. In English and Japanese.
Tokyo Connections http://www.tokyoconnections.com/
The site lists over 200 English-language resources for finding jobs in Japan, and for Japanese speakers looking for work overseas. It covers the whole spectrum of employment possibilities, from IT positions to postdoctoral research grants, and has an extensive section on English teaching jobs.
ELT News http://www.eltnews.com/eltnews.shtml
Website for English teachers, includes a classifieds section.
The JET Programme http://www.mofa.go.jp/j_info/visit/jet/index.html
Established in 1987, the Japan Exchange and Teaching (JET) Programme invites young college and university graduates from overseas to participate in international exchange and foreign language education throughout Japan.
O-hayo Sensei: The Newsletter of Teaching Jobs in Japan http://www.ohayosensei.com/
Each issue of O-Hayo Sensei lists 80+ positions at all levels -- from entry-level conversation school jobs, to lecturers and professors at national universities. The newsletter also contains a free classified ad section.