2013 will be the 50th anniversary of Martin Luther King's "I Have a Dream" speech.  The Historical Society of Pennsylvania has gathered some of its collection related to the civil rights movement into one section of its into website's' education portal. 

These materials also serve as a resource for students participating in THE DREAM@50 art contest, commemorating the 50th anniversary of Martin Luther King Jr.’s “I Have a Dream” speech.
K-12 students in ten cities, including Philadelphia, are invited to submit artwork inspired by a word or phrase from Dr. King’s Dream Speech.

Even after the contest deadline, this website has lots of great resources for teaching about the speech - from lesson plans to discussion starters and videos.  It also announces Dance the Dream, a series of flash mob dances to occur on August 28, 2013.