I believe that AT&T's International service can be up- and downgraded at will, so if you know you're going out of the country you can call them and add it to the plan, then when you get back you can discontinue it with no penalty. (IIRC - definitely check with them first, but I remember hearing this when I was contemplating my calling plan.)
Skype is also a great option when you have wireless access. My wife & I called home from Israel daily during a 9-day visit and it was next to nothing per call.
If you're prone to dropping your phone (like I am) I suggest a case from Otterbox. I have the Defender series. It's $49.95, but I've dropped my phone many times, including on concrete, and it's still purring right along.