If you want to have access to your US phone number, then you should add an international calling plan to your line. If you want to use the local carrier, then you should get the iphone 4S unlocked for overseas GSM networks.
The air card might depend on if it is global ready or not. The international data charges are quite pricey.
bozo33, a trip to Paris, France sounds LOVELY!!! Check out our Trip Planner to see what you need to do here: http://bit.ly/OFyn7n! Have a wonderful trip!
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