Update 23/10: Lexifone has contact us to say that its service launched in July 2012 and is available now. To use the service, you can purchase credit from the Lexifone website.
The first real-time voice translation solution is set to begin rolling out next month.
There are several companies that have real-time voice translation technology in the pipeline – Lexifone, Vocre, Microsoft and Alcatel-Lucent are among those developing software – but it is Japanese mobile network, NTT Docomo, that will be the first to begin rolling out its software on November 1st.

NTT Docomo, Japan’s largest mobile network, demonstrated its Android app earlier this month. Its technology provides users with voice translations of the other speaker’s sentence after a slight pause and also provides a text readout.
The NTT Docomo app is mainly aimed at businesses to begin with. Users must subscribe to one of Docomo’s packages to be able to use it.
French company Alcatel-Lucent is also close to launching its real-time voice translation technology, which differs from other services in that it works over a normal telephone landline and therefore does not require a data connection.
The NTT Docomo app will initially convert Japanese to English, Mandarin and Korean. Support for French, German, Indonesian, Italian, Portuguese, Spanish and Thai will then added in late November.
More info available on the BBC website
Thanks for mentioning Lexifone here. I wanted to make one correction. Lexifone has already launched back in July 22 2012. Visit our website http://www.lexifone.com, buy credit and start conversing with people who do not speak your language all around the world.
Wow of this goes mainstream then it will be a real benefit to a lot of people out there who feel either pressured into learning the most commonly used language in their area or restricted to who they can call because they are worried the recipient will not understand them. However after reading this blog it finally seems that there is going to be a real time phone translation service that is implemented during calls.