UMass Lowell Career Services
Idealist - Nonprofit jobs locally and around the world. Search by location or type of job, plus sign up to get emailed new job listings. They also run career fairs.
New England Jobs - New England nonprofit jobs. Sign up to get emailed new listings.
Tufts University Department of Urban & Environmental Policy & Planning has a jobs page with lots of good links.
Commonwealth Seminar Jobs Page - Organizing, advocacy, political, and social service jobs in Massachusetts
Nonprofit Times - business publication for nonprofit management.
Organizers for America - Includes a Job Bank of progressive activist jobs.
Union Jobs - Job listings from labor unions
Colorlines Magazine - Has a few classified ads (mostly progressive social movement jobs)
E-Jobs and Sustainable Business - Both list environmental jobs and environmentally sustainable employers.
One World - Jobs in global development
American Society for Public Administration - Includes job listings in government, nonprofit, and university settings.
Non-Profit Jobs - Community Career Center, lists nonprofit jobs from across the country.
American Planning Association - Jobs for planners