Remittances to Mexico: $23 billion in 2006
Remittances to Mexico - money sent from legal and illegal immigrants in the U.S. to friends and relatives in Mexico - rose to $23 billion last year. That figure is from Mexico's Central Bank; the Inter-American Development Bank's estimate is $2 billion higher.
This is up from $10 billion five years ago, so obviously some of the increase is due to better accounting. Some is also due to lower costs to send money; note that the Federal Reserve is completely corrupt and is trying to profit from illegal activity by tapping into this market and helping member banks do the same.