The Department of State offers you very useful data and information about overseas schools which have familiar American curricula and teaching methods.
This educational portal lists the private schools both national and international available to you in Argentina.
This site has listings of all the non-government or private schools in Australia. It also has a convenient map interface to help you find what you are looking for.
The United States Department of Defense operates schools for children of service people around the world. You will find websites for the four main geographic areas in which DoDEA has a presence.
ECIS is the grandfather in the family of international school directories and associations. You will find over 400 member schools in 90 countries on this site. If you are looking for a school in Europe, start here and work out.
The Good Schools Guide offers you more than just listings of schools in the United Kingdom. It has seemingly endless resources which should help you immensely if you are a British parent checking out private schools.
Hobson's has a very helpful interface which allows you to select schools according to your own specific criteria. The site also has a wealth of information covering everything from paying school fees to making the application.
The ISNZ site gives you data and information on slightly more than 40 private schools in New Zealand. You will also find help with selecting schools, information about scholarships and teaching vacancies.
The ISD site contains entries for over 2,000 schools. You will find all the help, advice and guidance you need in choosing a private school in the United Kingdom.