Just now I have called 07589007045 from Orange and somebody picked up the phone. He started asking questions regarding which country you want to call and service provider etc-etc. He has just started explaining like you can give me your number and the service provider, I can give you nice number to call the country you want to call for free. i.e.you can use your cross network minutes.
Lastly, he said you can go to the website
http://www.07589.co.uk When I tried that site it is redirecting to
http://www.free-international-calls-on-mobiles.com/ Hope this information may help some one.