You can do international rotations with any residency at any program. Four-year emergency medicine programs usually offer more electives, and thus more time for international rotations. Three-year programs typically only offer 1-2 months of elective time, which makes it difficult to arrange international rotations as most require 4-6 weeks plus your travel time. (Provided you want an adequate experience. You could always go for a week or two if that's all you want.)
The majority of our residents do international rotations. We've had rotators in Ecuador, South Africa, Eritria, Bolivia, Fiji, New Zealand, and more recently, Vietnam, Mexico, and Zambia (just to name a few). A lot of residents are attracted to our program because of international opportunities. Although we currently do not offer an international medicine fellowship, we do allow you to spend up to 5 of your 6 months of elective time away from the institution.
Check out the Yale/Johnson & Johnson International Scholars Program. The Yale/J&J programs pays up to $5,000 for your rotation. Half of the selected applicants are from our institution, but the other half come from non-Yale residents.
The link is:
http://info.med.yale.edu/ischolar/
Currently the program offers rotations in about 15 countries. You can set up your own rotation in any country, but this takes more time as it must be approved by Yale School of Medicine, even if you aren't a Yale resident.