In countries like Guatemala, remittances from migrant workers in the U.S. are critical to the economy. Tigo, an international telecom, has a unique plan to use mobile banking to simplify a trying process.

Every week or so, Nehemias Navas-Perez, 32, a Long Island, New York, landscaper, trudges over to the local Western Union or Intermex to send a couple hundred dollars to his family in the jungle-covered outpost of El Peten, Guatemala. Remittances from folks like Navas-Perez, who emigrated from El Peten 11 years ago, can account for 11% of GDP in small countries like Guatemala, and create huge international money flows each year: In 2011, World Bank figures indicate that there were $483 billion in such remittances worldwide. The stream runs pretty consistently. According to Dilip Ratha, manager of the World Bank's migration and remittances unit, international transfers fell just 5% in 2009, the nadir of the recession, before quickly rebounding