"Remittances are transfers of money by foreign workers to their home countries.
Money sent home by migrants constitutes the second largest financial inflow to many developing countries, exceeding international aid. Latest estimates vary between IFAD estimates of US$401 billion and the World Bank information from central banks at a more conservative US$250 billion for 2006 and these figures are increasing by almost 30% year on year. Remittances contribute to economic growth and to the livelihoods of needy people worldwide. Moreover, remittance transfers can also promote access to financial services for the sender and recipient, thereby increasing financial and social inclusion."
Read the rest of the Remittances page here.
The actual $ figure for money sent by people with ties to other countries (family, etc.) is probably higher than estimated in the Wikipedia page because it is not only "foreign workers" who send money "back home" on a regular basis but also others who have permanently settled in the "first" world, and in some cases their children and grand children - born in the "first" world but still with functional ties to the ancestral homelands.
Nice to see that so many ordinary people participate in these trans-national, trans-continental economic transaction; a world/millions of people connected by wire transfers :)