Upton Sinclair's The Jungle
http://www.youtube.com/watch?v=m1U0kXX0RAM
A short documentary film describing the historical context of Sinclair and the motivations for his novel.
The Jungle by Upton Sinclair
http://www.online-literature.com/upton_sinclair/jungle/
A searchable complete text of Sinclair's novel.
The Jungle
http://en.wikipedia.org/wiki/The_Jungle
The Wikipedia entry for Sinclair's novel.
Upton Sinclair: The Jungle - speech on socialism
http://www.youtube.com/watch?v=C62Q9tAbG3I&feature=related
This is an audio reading of the socialist speech that first awakens Jurgis to the socialist movement at the end of the novel.
Socialism in America
http://www.u-s-history.com/pages/h1669.html
A brief history of the socialist movement in American culture and politics.