Bing Translator (http://www.microsofttranslator.com/Default.aspx) enables TTS output for translation result last week. You now can not only know what the translated results would be but also learn how to read the translated results in the language by clicking the speak button on the top of the result window. Currently TTS are enabled on these target languages: English, German, Spanish, French, Italian, Portuguese, and Russian.
Bing Translator also comes with an API (http://msdn.microsoft.com/en-us/library/ff512420.aspx). Developer can call the API to speak a piece of text and get the TTS wave output stream easily. For a code sample, check out this blog.
For more details about Bing Translator, check their blog.
If you have any feedback on the voices with the translator, please comment.