Traveler turned teacher

Try eslcafe.com. There is a very active forum by country if you have specific questions.

mel,

Peacecorps is one.

If you have any local community college in your area see what they have.

happy trails.

melanie don't forget that you will need an appropriate work visa if you are working as a teacher.

Do you want volunteer or paid opportunities? A friend of mine has done several volunteer stints that were more-or-less 100% volunteer (had to pay for his own room and board) in Asia and Africa. Another friend who is a veteran teacher got a place on a volunteer program in Australia's outback. I believe she paid her own airfare, but all her local expenses were paid for and she received some spending money from the program too.

I don't know if you're an actual credentialed teacher or just want to teach English overseas.....
These are the two companies that most credentialed teachers who want to teach abroad use to find positions at reputable schools who are looking to fill administrative and teaching vacancies. They both run job fairs all over the world to find good candidates for the institutions who use them to find staff.
International School Services
Search Associates
There is a huge variety and quality of overseas "schools". Some of them are small, amateurish and don't pay well at all. Be very careful and do your homework so that you don't end up working at a place that is not well-run where you are barely making enough to live. Most of the schools listed on ISS and SA are going to be established schools that are professionally run where you will be able to build a career.
If you want to teach English overseas you'll need to get your TESOL or TEFL certificate to get a job. No reputable place will hire you without one or the other. This site lists many places hiring people to teach English as a foreign language. Again, wide variety of institutions...be very careful with these kinds of schools and know what you're getting into before committing to anything.

Here are some reputable websites applicable to K-12 teaching. Is that what you are interested in?

Many overseas American and International schools are affiliated with the US State Department Office of Overseas Schools. Go to www.state.gov and search for Office of Overseas Schools. (ISS and Search Associates recruit for these schools among others.)

The US Department of Defense has schools. http://www.dodea.edu

Church and mission agencies have schools for missionary kids. A partial list is here: www.ismk.org

As already state, there are many, many English teaching institutions.

Good luck.