Are you talking about free calls specifically with the Orange network? Because Carphone Warehouse have the Talk Talk service where if you have a BT landline, you get free calls to other Talk Talk customers and free broadband up to I think 4Mb.
I think he is talking about the thing were if you're on Orange you can call any other Orange mobile phone for free after 7pm (or it might be 6pm). I myself am trying to find out what this package is called - I know it's on a pay as you go thing anyway. But trying to explain to their customer service department - who (when i'm back from college) goto India... it's too much hassle. Actually come to think of it, I'm going to a weekly group thing tommorow evening and one of my mates there works for Orange. I will ask him for you and I.