231 Pennsylvania Ave. Call early to reserve. You can order passes online, or call 962-1234. In Washington and other U.S. locations, the VoiceStream company allows GSM-based international roaming. Those whose GSM-based phones do not work on other frequencies can bring the ''smart card'' that carries their personal preferences and slip it into a phone rented from Cellhire, allowing them to receive calls placed to their usual number.
Rental phones are available at airports, at car-rental firms and through some hotels.
Don't forget your warranty. Brian Knowlton is the International Herald Tribune's correspondent in Washington.