You might need to get a new chip for the phone. You can get chips that are for each "country" (e.g. Spain and Portugal chip) or a chip that is for most of Europe. The per country chip should be about 25 euros. From the plans I explored (which was not extensive), the Spanish calling plans are more expensive than the ones in the U.S. (different rate structure), but cheaper than using your U.S. phone plan in Europe.