From the Skype Blog:

“Today, we are excited to announce the first phase of the Skype Translator preview program. The preview program will kick-off with two spoken languages, Spanish and English, and 40+ instant messaging languages will be available to Skype customers who have signed-up via the Skype Translator sign-up page and are using Windows 8.1 on the desktop or device.”

There’s a video of the Skype Translator Preview in action with two schools one in the US and one in Mexico having a real-time conversation in English and Spanish

One can register for the Skype Translator Preview at
http://www.skype.com/en/translator-preview/

A Skype Garage Blog Post goes into the technology behind Skype Translator , with an Infographic on how Skype Translator works and video