CARE
This web service of CARE is organised in two separate sections: positions within the US; and positions outside the US.
An RSS service is available.
Languages: EN
http://tbe.taleo.net/NA5/ats/careers/jobSearch.jsp?org=CAREUSA&cws=1

LGI-OSI
This is the Local Government and Public Service Reform of the Open Society Foundation, which has a specific geographic focus on Eastern European Countries.
They publish a vacancy page that needs to be monitored, as in the recent weeks we did not notice any announcement. One can subscribe to their automatic broadcasting system.
Languages: EN RU
http://lgi.osi.hu/announcements_list.php?type=5

OXFAM
This is the page where Oxfam publishes its vacancies, but also a gateway to the different national pages of the organisation, where national opportunities are advertised.
Languages: EN FR SP
http://www.oxfam.org/en/getinvolved/jobs/index.htm

The Rockefeller Foundation
The openings at the Foundation are very few, but from time to time there are some opportunities in the evaluation sector.
Languages: EN
http://rockfound.org/about_us/careers/jobs.shtml