I too have an AT&T Iphone4. I just tell the wife, kids, friends, etc. to text me if I am overseas (25 cents to receive a text, 50 cents to send). I turn on call forwarding when I am on an overseas trip so I don't get charged for incoming calls that I don't answer. You have to call AT&T to get unique number for your phone to forward to. My phone's voicemail includes a note to send me a text if they don't get an answer. I'm also a Skype advocate.