Last April, Bing updated the Bing Translator for Windows Phone app, including a number of new features like the ability to use the camera to get a translation of printed text (like a menu or a street sign), offline translations, and translations via speech or keyboard input. Now the app has been updated for Windows Phone 8, and to version 2.5.
We had a bit of trouble getting to the app via the Windows Phone Store web interface (not sure if that was a problem with the Store or just that the app is still new), and searching for “Bing Translator” didn’t get us there either, but if all else fails, you can bring up this blog post on your Windows Phone 8 device and get the app from here.