IPA (The International Phonetic Association): International phonetic alphabet. Also links and information about phonetics. Phonetic Fonts for Windows and Macintosh.
Sounds of English: Pronunciation help for learners of American English and their teachers. Material contributed by both Sharon Widmayer and Holly Gray. From the the Maryland English Institute, University of Maryland.
SoundsofEnglish.org: English pronunciation with pictures, sounds, and videos. Pronunciation and listening activities.
Also tips for teachers, listening exercises with printable worksheets and teacher guides.
Stuff Media Interactive Education: Phonetic Calculator. Learn the sound and characters of the international phonetic alphabet with this amusing software.
The New Okanagan College: English pronunciation and listening. A collection of videos and mp3 files about specific English sounds. For all foreign and domestic students who wish to improve their English.