AT&T Natural Voices (allows downloading!) :
http://www2.research.att.com/~ttsweb/tts/demo.php
Interface language: English
Text to speech:
http://www.oddcast.com/home/demos/tts/tts_example.php?sitepal
Interface language: English
Acapela:
http://www.acapela-group.com/text-to-speech-interactive-demo.html
Interface language: English, French
These useful tools allow you to write some text and then hear it with various english accents so that you can get used to them and also have a example for your speaking.
Self access online resource center for french language.
