The main page for the web version of Sounds of the World's Languages. Go here to hear native speakers of many, many languages producing all sorts of interesting distinctions. Try the maps page to just explore.
The Praat web page: http://www.praat.org. Download and install Praat here, or join the Praat help listserv.
Speech in many, many dialects of English (as well as many foreign accents), much of it phonetically transcribed, and all of it available to listen to: http://classweb.gmu.edu/accent/.
University of Iowa has a great site that shows you animations of English and Spanish speech sounds, a video of a speaker's face producing the sounds, the IPA symbol, and along with all of this plays the sound. Good for IPA, articulations, and audiovisual speech.http://www.uiowa.edu/~acadtech/phonetics/
Movies of pharyngeal consonants and of the vocal cords: http://web.uvic.ca/ling/research/phonetics/index.htm. This page has the movies to go with several papers by John Esling (I'm having problems with some of these movies, but they're great.).
Baldi audiovisual synthesis (audiovisual speech synthesis, with multiple languages and special effects). A Baldi toolkit is also available here, if you want to do audiovisual synthesis for your paper.