A: When in Rome, do as the Romans do. Switch out your SIM card -- the little chip in the phone that carries your account information -- for a prepaid local one, and pay local rates.
The SIM card, or Subscriber Identity Module, is almost always located in the phone's battery compartment. You'll probably have to remove the battery to get at it, but you don't need any special tools.
You do need to do some homework first, but it's worth it, unless you're just staying in the foreign country for a few days. U.S. carriers generally charge about $1.29 per minute for international roaming, while local prepaid rates are around 20 U.S. cents per minute for outgoing calls, and incoming calls are free.
There are a couple of hurdles here, though. For one, not all U.S. phones work in Europe because of differing radio frequencies and technologies. The chance that your phone will work is best if your carrier is T-Mobile USA or AT&T Inc., but check your manual or the carrier's Web site to see if you have a "world phone."
Except for a handful of models, Verizon Wireless and Sprint Nextel Corp. phones don't work in Europe (and don't use SIM cards), but do work in parts of South America.
If you do have a "world phone," it still has to be unlocked for it to accept a SIM card from another carrier. Contact the carrier: It might give you the code to unlock the phone. Otherwise, an independent cell-phone store might be able to do it for a fee.
Putting a local SIM card in your phone means you're now using a local number. The good thing about this is that locals can call you cheaply, instead of dialing your U.S. number.
The downside is that people calling you on your U.S. number won't reach you, just your voice mail.
Of course, there's a way to deal with this.
An account with a Web site such as TollFreeForwarding.com gives you a U.S. toll-free number that will forward to an international number for $10 a month, with about 90 minutes of talk time included for calls forwarded to Western Europe.
Then, set your phone to forward to the toll-free number (ask your carrier for instructions). Incoming calls will bounce from your U.S. number to the toll-free number to the overseas number.