From the IRS
Financial institutions and tax administrators that have an obligation under U.S. tax law to report account information to the IRS now have a secure online site where they can transmit that information, the IRS announced.
The site, called the International Data Exchange Service (IDES), offers a web-based application that provides for encrypted transmission of data. Senders are expected to use a standard XML schema format that captures information the U.S. government is collecting under the Foreign Account Tax Compliance Act (FATCA) and to encrypt the data before transmission.
FATCA requires foreign financial institutions to report to the IRS information about financial accounts held by U.S. taxpayers or by foreign entities in which U.S. taxpayers hold a substantial interest. Some countries have agreements with the United States under which the countries' tax administrations collect the information from domestic financial institutions and forward that information to the IRS.
Financial institutions and tax administrators can enroll and create an online account at the IDES website, which is available at www.irs.gov. The website includes an IDES frequently asked questions page that addresses technical issues about the system.