International Federation of Social Work has lots of general information and resources regarding international jobs in social work, including additional helpful links.
DevNetJobs.org is a database of national and international job postings in non-profits, NGOs, consulting, and more.
InterAction is a coalition of more than 150 non-profit organizations working worldwide. The InterAction Job Board acts as an interface between job seekers and our members, other non-profits, NGOs, and academic institutions.