I would definitely check out the link that Michael posted first
Facetime though is an app that is very much alike to something like Skype. You can video chat people via other Apple desktop, laptops, and iOS devices.
Assuming that I got both Facetime and iMessage working for the first time by activation.
My question is, will Facetime and iMessage keep sending this international SMS to an UK number every time I reboot my phone and I get charged for the SMS every time my iPhone reboots?
I have a factory unlocked iPhone 4 on Vodafone UK network (My plan doesnt have any free text in that)