The World Bank estimates that remittances to developing countries in 2011 exceeded $370 billion. Here's some context, from the "Migration & Development Brief":
It's interesting to see just how thoroughly remittances dominate ODA (official development assistance) as a source of funds in developing countries. The chart also shows the explosion of FDI in the developing world over the last 10 years (interrupted by the financial crisis but recovering quickly).
Hat tip to the Roving Bandit!