Woody Guthrie's Official Site
The site includes a good biography and a detailed listing of the contents of the Woody Guthrie archives.
PBS's Dust Bowl
This page is dedicated to Ken Burns' documentary series, but from here, you can check out biographies, an interactive Dust Bowl tool, photos, and more.
PBS's Dorothea Lange Biography with Photo Gallery
Photographer Dorothea Lange took an iconic series of photos of Dust Bowl migrants in the 1930s, and you'll probably recognize some of her images immediately.
The Library of Congress' "Voices from the Dust Bowl: the Charles L. Todd and Robert Sonkin Migrant Worker Collection, 1940 to 1941"
This is an informative collection of pages, full of clear information, articles, and compelling photos on the Dust Bowl migration.