http://www.irs.gov/Individuals/International-Taxpayers/Forei...
Source of Earned Income
The source of your earned income is the place where you perform the services for which you received the income. Foreign earned income is income you receive for performing personal services in a foreign country. Where or how you are paid has no effect on the source of the income. For example, income you receive for work done in France is income from a foreign source even if the income is paid directly to your bank account in the United States and your employer is located in New York City.