Thanks once again to Gary Price's ResourceShelf for this tip:
The University of Virginia's Miller Center of Public Affairs—Scripps Library & Multimedia Archive is the repository for a remarkable collection of U.S. presidential speeches. The audio files, as well as the full-text "transcripts" of pre-F.D.R. speeches, are wonderful multimedia educational artifacts. Here's some information, straight from the Miller Center's Web site:
The Scripps Library, through cooperation with various presidential libraries, has been collecting some of the more important presidential speeches of the past 60 years. These speeches are available in their entirety in full audio. When possible, we have also provided transcripts of the speeches. Recently we have expanded our collection to include the full text of some of the more important presidential speeches from the 18th and 19th centuries.
Click HERE to access the speeches.