I have just heard about this tool which translates text to speech in different languages. It seems to be a great tool. I've tested it with a short text in English and checked the translation into Portuguese, Spanish and French (the languages I can understand) and I am impressed with the result. Of course whatever you type in English can simply be converted into speech and I can see a lot of potential for students to improve their pronunciation.
All in all, I highly recommend you give it a try. Take a look here and enjoy it.