US National Archives
Internet Archive: The Dream of Kings
Original footage [23:00] of Martin Luther King's "I Have a Dream" speech.
American Rhetoric
American Rhetoric: Martin Luther King, Jr.
Martin Luther King at the Lincoln Memorial, with text and audio version of the "I Have a Dream," speech.
Stanford University
Stanford University: King Institute: Encyclopedia: "I Have a Dream" Speech
Archival audio version of King's "I Have a Dream" speech, with transcripts available in multiple languages.
Other
Reading Through History: Martin Luther King Jr.'s "I Have a Dream" Speech
The defining moments of Martin Luther King Jr.'s "I Have a Dream" speech during the March on Washington. [5:24]