FORVO: the Pronounciation Guide. Their slogan says it all--"All the Words in the World. Pronounced."
At present over 1,500,000 words and 1,600,000 pronounciations representing 300 languages are available. Click the play icon next to a word to hear it pronounced. Languages with the largest number (100,000+) of pronunciations are: German, English, Russian, Tatar, and Portuguese. See the complete list for all languages available on the site.
You can also register and take part in creating FORVO, whether by asking for a pronounciation or recording words in your own language for others.