Former British colonies are important from a genealogical perspective for several reasons: they have been the destination of emigrants from the British Isles (some voluntarily, some less so), the source of much immigration and a place of work and residence for British merchants, soldiers and others.
The American colonies were the first to receive convicts and there is a superb research guide on The National Archives site giving details of the records held. More general information about colonies on the other side of Atlantic as well as reference guides to post-colonial emigration to the USA can be found, linked from this guide.
The US National Archives and Records Administration has information on immigration and naturalization – as they spell it – on the Archives.gov website and Ancestry has databases of Immigrants to New England (1620-33), New England Immigrants (1700-75), New England Irish Pioneers and Scots-Irish in Virginia. For the late nineteenth and early twentieth centuries, Ellis Island has a searchable database of passengers who entered through Ellis Island between 1892 and 1924. And that’s just the beginning….
For Canada, there is less immigration material online, though Marjorie Kohli’s Immigrants to Canada site has an extensive collection of material and links to a whole host of resources. Passenger lists are steadily being digitised and made available on the various commercial sites.
What did we do before the Internet? We simply would not have dreamt of having access to these types of records twenty years ago!