ProWorld

ProWorld has a great variety of volunteer, internship and study experiences in many different countries- many focused on Central America and South America, but also India, Nepal, Ghana, and Thailand.


The study aboard programs mostly are language immersion, service-learning, and field study programs at local universities.

Many of the internships are very unique to the culture and location. For example in India you can do a health internship at a ashram! or in Mexico help kids with disabilities ride horses. Have to say...that's pretty cool. 


They also have scholarships for certain projects and referral incentives. 

Proworld

Global Vision International

This is another organization that provides flexible and customizable abroad experiences. There are volunteer and internship opportunities that can last as little as 2 weeks or as much as more than 6 months. They have projects offered on very continent (except for Antarctica). They also have "expeditions" which seems to be a combination of volunteering and tourism with a group, they mostly focus on environmental and wildlife themes but there are community expeditions.

http://www.gviusa.com/

Volunteering: 

• with Children (teaching, arts, sports, social work, childcare)
• climate change 
• marine conservation
• Teaching English abroad
• Construction
• Community
• Wildlife and Conservation

Internship:

• Environmental
• Non-profit
• Humanitarian
• Responsible Business

Idealist.org

If you are a social worker, volunteer, interested in non-profit work, or just an overall do-gooder and you haven't heard of Idealist.org you MUST check it out. It's a great hub for jobs, internships, volunteer opportunities, and networking.

It's not necessarily for international placements, but it does have links to international non-profits and domestic organizations that do work abroad. They also travel around the country to host volunteer fairs at university campuses like UCLA.

Idealist 

i-to-i Volunteer and Adventure Travel

This seems to be more of those organizations that "work hard, play hard" - combining some volunteer serving with tourist activities.

They specialize in offering TEFL (Teaching English as a Foreign Language)

They offer programs by the week up to 12 weeks, but they also have some special internships every year for 2011 it's for China and Thailand.

http://www.i-to-i.com/

United Planet

United Planet seems like a well-organized program with a good, solid reputation. They have a wide variety of programs- there's pretty much something for everyone.

* solo travelers
* college/ grad students
* families
* corporate groups
* teens
etc.

40 countries to volunteer in - there's at least 1 program in every continent (except Antarctica!)
Including: Tibet, Ecuador, Cambodia, Romania, and Jordan.

Another unique feature they have are "group" trips organized and customized for groups.

* Social work related internships in Peru, Nepal, and Jordan!
* Spanish immersion

Global Experiences - Get an Edge in Life

While they don't have "social work" internships per se, they do offer many internship areas that could be very useful and related to social work: education, communications, government, law, etc.

http://www.globalexperiences.com/general/careers.php