There are many good resources on slavery on the internet, but most of the ones I have found deal with post-colonial America. For the colonial period, which bears directly on the history of early modern Europe, see The Impact of Slavery at the Internet African History Sourcebook. This site includes interesting personal narratives, including some from former slaves.

The Atlantic Slave Trade and Slave Life in the Americas: A Visual Record offers a searchable database of some 1,200 images. (Collection by Jerome S. Handler and Michael L. Tuite, Jr.; hosted by the University of Virginia Library.)

There is a short reference to the first Africans in Virgina in 1619 at the Gilder Lehrman Center for the Study of Slavery, Resistance, and Abolition. The National Park service offers a chronology of African Americans at Jamestown with suggestions for further reading, and Virtual Jamestown offers a selection of seventeenth-century slave statutes.

The poster shown here looks like it is from the eighteenth century. Unfortunately, the source from which I obtained it provides no details: http://www.peacebuttons.info/E-News/peacehistorymarch.htm