The University of Illinois' Modern American Poetry site features some fantastic information on McKay. Here you'll find a biography, some great analysis of his poetry (including "If We Must Die"), scholarly essays on the poet, and more.
McKay's biography and selected poems on the Academy of American Poets' website.
A web version of the collection of poetry in which "If We Must Die" was first published.
This PBS article provides some background on the 1919 race riots that inspired McKay to write "If We Must Die."
McKay leaning against the wall, smiling back.
The poet as a young man.