In most cases you will be paid in the local currency. Before you sign a contract make sure you know the exchange rate between the currency in your country of origin and your potential host country. This is a great link to bookmark: Universal Currency Converter -
www.xe.com
Some schools in Middle Eastern countries, particularly Kuwait and Saudi Arabia pay in U.S. Dollars. If this is the case it will be specified in your contract. International schools affiliated with the U.S. government or military also pay their teachers in U.S. funds.