Most companies do not require anything more than a passport to work. There are a lot of US companies in the country, especially in Santo Domingo and DN the National District. There are good opportunities for English speaking employees. The country has several free zones, lots of them in the call center area.
Many US universities offer study abroad options for the Dominican Republic. The two most common cities hosting exchange students are Santo Domingo and Santiago. Check with local universities for programs and prices. Spanish language schools are located in major cities and on the north coast as well.
There are several volunteer opportunities in the Dominican Republic. Many worldwide organizations offer extended travel for anyone willing to volunteer their time to work with locals on projects such as community development, conservation, wildlife sanctuary maintenance & development, scientific research, and education programs.
Orphanage Outreach (http://www.orphanage-outr...)
Dominican Foundation (http://www.dominicanfound...)
International Student Volunteers Dominican Republic (http://www.isvonline.com/...)
The DREAM Project (http://www.dominicandream...)
Peace Corps Dominican Republic (http://dominican.peacecor...)