During this years Microsoft Mix conference (which Niels, Paul Sterling and I attended) Microsoft Translator was announced (along with alot of other great stuff, which you can find on the mix site)
Microsoft translator is a Machine translation webservice, so you simply tell it to translate a piece of text from one language to another, it is very impressive and really really fast.
Integrating it with umbraco was a breeze, actually it was done during the translator Q&A session which took place at mix, half an hour of coding in total, which resulted in near-instant translation of new pages added to an umbraco site into multiple languages from english.
Now sit back, and enjoy the music while you view the video below to see how this works:
And then download this zip file to get the code.
How to use:
Copy the translatehandler.cs to the app_code folder, and setup the different configuration values. And get a AppID from microsoft here (it's free)