microsoft Researchers at are working on a System for real time translation of Voice on calls. This is an extension of multiple features already supported by various applications. Currently various Call centres use a real time transcription of English – English VOIP calls for the purpose of documenting and making these calls searchable. And search engines like google and Bing are able to provide translation of search queries, web pages etc.
And if a transcription system can be achieved for each language, the real time translation between various languages for Telephone system wouldn't be far off. With such a system global business can be simplified without need for translators and language borders will also vanish.
Direct link to microsoft research – http://research.microsoft.com/en-us/news/features/030310-behalf.aspx