Skype is a good option. When we come down to AR, we have our US cell numbers forward the calls to our Skype US numbers, which rings on our computers and iPhones here in AR. The forwarded call in the US is either free or small fee (US # to US #, depends on carrier and plan) and receiving calls on Skype is free. It's seamless for our friends and family in the US (they keep calling the same # to reach us, whether in the US, AR, or anywhere else). The only costs involved are buying your Skype online number, and adding some $ credits to it to make outgoing calls.