A reader pointed me to a site which may be useful for international travelers. The purpose of the site is mainly focused on unlocking phones for use across different phone carriers, but they also provide free tools and guides (http://www.uniquephones.com/Phone-Travel-Guides.html).
One tool, checks phone compatibility for a specific country given a make and model. For many of the cases, it is just checking if GSM is supported in the country since a GSM phone will work in any country as long as you have a SIM card (pre-paid or belonging to a supported carrier) installed in the phone. I cannot vouch for the accuracy of every combination, but it’s worth a check if you’re planning to make a trip into another country and want to make sure your phone will work. You can also go to many of the GSM-related sites and just look up the country you plan to visit. If you have a GSM-compatible phone, you’re good to go.
I’d stay away from another tool which allows you to estimate expected roaming charges when using your phone in another country based on your current carrier. I punched in a few values and it doesn’t appear to calculate the dollar amount very accurately. In fact, I tested 0 for all the input values but it still gave a high cost due to roaming. Looks like a ploy to get to you to signup with one of the SIM card providers.
Looks like mixed reviews for the unlocking services so user beware.
Thanks, Vikki.