To make the Verizon iPhone international it would have to have a GSM chip and a CDMA chip. The rest of the world runs on GSM, which Verizon uses CDMA.
So, if you’re doing a lot of overseas travel for business, you probably want to go with the AT&T iPhone.
However, if you read the official Verizon iPhone FAQ, it says otherwise:
Can I use my iPhone 4 while traveling abroad?
Yes, customers can use iPhone for voice and text in over 40 countries with data service in over 20 countries. For service availability and rate information, visit International Roaming Rates and Coverage. When travelling outside of these 40 destinations, the Global Travel program is the perfect short-term solution for the occasional or infrequent global traveler who needs to stay in touch when travelling internationally.
How very odd. I wonder who’s right?