Find out more on these links:

http://www.windowsphone.com/en-US/apps/3107b64f-7f25-e011-854c-00237de2db9e
http://www.bing.com/community/site_blogs/b/search/archive/2012/04/16/new-translator-app-for-windows-phone-powered-by-bing-available-for-free-download.aspx