The service is available through an agreement between the cruise line and Wireless Maritime Services, a joint venture of Cingular Wireless and the Maritime Telecommunications Network. Here's how it works: While at sea, guests can make and receive calls, send text messages, and transmit multimedia -- just as they would on land -- using their own cell phones; personal digital assistants such as BlackBerrys are also supported.
Though Carnival is providing the "signal" via Wireless Maritime Services, those who use it will be billed by their own carrier at set rates comparable to international roaming charges -- still far lower than ship-to-shore calls from the cabin. The service is compatible with virtually any cellular telephone; if staying in touch via cell is a must, you'll want to check with your carrier before setting sail to verify that your phone and calling plan will work.
Most mainstream cruise lines now offer cell phone service on some if not all ships (Princess is one notable exception). For more information, check out At Your Service: Connecting @ Sea.
--by Melissa Baldwin, Senior Editor