Microsoft has just announced the availability of the Microsoft Translator Hub for commercial use, including access to the Microsoft Translator API. Microsoft Translator Hub is built on Windows Azure, and provides tools for businesses to "build, improve, and deploy customized automatic language translation systems."
The KantanMT's REST-based API with JSON responses is designed to aid mid-sized local service providers (LSPs) in delivering KantanMT translation capabilities. KantanMT is a statistical machine translation platform (in contrast to a computer assisted translation service). The big advantage is speed: the service is available instantly, faster than you can say, "qu'est-ce que c'est?"