This is great!
http://i100.independent.co.uk/article/this-great-map-lets-you-explore-the-history-of-migration-for-every-country-in-the-world--b1xiciWtpBe
Scroll down for the interactive version.
The map is cool although I'm certain that the data is definitively incomplete and underestimated in a number of cases (or at least I can tell by looking at Colombia's inward and outward numbers).