Hey, good to hear you're interested in the overseas teaching lifestyle. Since we're on a financial forum, I'll preface it with: done right, you can save a good portion of your salary. However in many places the salary will be less than in the US. Teaching in an international school will get you a significantly higher salary and generally better working conditions than ESL teaching. However, if you're not up for getting qualified yet, ESL teaching can be a road to getting there. Many teachers get certified/their MA's while working overseas. Or you could start out ESL teaching then look at university opportunities on site.
Like Nikki, I work in Asia, which is a big market for ESL teaching, and the most lucrative. You'll want, minimum, a TEFL certificate. A CELTA would be great, especially if you're interested in teaching in/near Europe eventually.
You'll want to lay out your priorities: how important is a particular culture to your next step? How about savings potential? Lifestyle? Every country will fulfill a different set of criteria. For ESL specifics, DavesEslCafe.com is a great place to start.