Librivox
http://librivox.org/

Free Classic Audiobooks
http://freeclassicaudiobooks.com/

Project Gutenberg - Audiobooks
http://www.gutenberg.org/wiki/Gutenberg:The_Audio_Books_Project

Learn Out Loud
http://www.learnoutloud.com/Free-Audio-Video#directory

Tell Tale Weekly
http://www.alexwilson.com/telltale/spokenalexandria.php

Thought Audio
http://www.thoughtaudio.com/index.html

Podiobooks
http://www.podiobooks.com/

NPR (National Public Radio)
http://www.npr.org/rss/podcast/podcast_directory.php

Denver Public Library
http://podcast.denverlibrary.org/

Kankakee Public Library
http://www.kankakee.lib.il.us/Podcasts.html

AudioFile Magazine & links to Audiopolis and Earshot
http://www.audiofilemagazine.com