Have you tried using Google Voice? You can make inexpensive international calls through it. The update for Android offers a new interface and a feature called asynchronous SMS. You can prepare your text message even if you're offline and have the phone send the message once you have reception (nice feature if you spend a lot of time on the plane writing messages).
I use Google Voice to transcribe my voicemails and to send SMS with my family (don't need to pay for text messages if you use an app like Google Voice).
I would highly recommend Google Voice for medical students and residents who: 1) have limited income; 2) need an effective way to stay in touch with friends and family; 3) want to read a transcript of their voice mail messages.