PowerLine has a post featuring quotes from the Letter from a Birmingham Jail that's well worth a click: The Prophetic Voice.

It's worth taking the time to read the whole letter, here, and the text to the 'I Have a Dream' speech here. There is also a 10-minute video of the speech available on this page (scroll down to 'eTexts/RealTime Videos of King's Speeches and Writings'), although the bandwidth appears to be getting hammered at the moment.