Introduction to Translation Proxies: Seth introduced me to these yesterday. Honestly, I’m slightly embarrassed to say that I had never heard of these before:
A translation proxy is a service that sits in front of your website and applies translations so that different audience segments can see your content in their local languages. You point various DNS entries to the proxy so that request goes through the proxy service to your native language website. On the return trip, the proxy applies translation rules to the HTML in the response.
Look at Smartling.