Well, I'm guilty of bringing my cell phone with me AND leaving it on while onboard the ship, especially if I'm cruising with my friend(s)  Just make sure you are on a land line cell tower network! Very easy to do with a Motorola Razr which is my phone, so I don't know about others out there. I just bring up "Available Networks" under the "Settings"; "Network" menus and register on the land network.
I have the international calling plan set up with my carrier, which is TMobile, so there is no monthly fee (AT&T is DH's carrier and they charge a monthly fee but less per minute on the ship and land towers). TMobile has a roaming agreement with AT&T/Cingular which is the carrier of the ship's towers. If you look at the "network" your phone is on and it is a network consisting of numbers vs a name (ie Italiafone or some other port name based on where you are currently sailing) you are on the ship's tower at $4.99/minute vs. $0.99/minute on the land tower (they are my TMobile rates). I just switch networks to the land one. By default it will normally go onto the ship's network since their signal will be stronger when you're onboard if you have roaming on so make sure to check your network when making a call or receiving one.
Lars has a great idea of programming the ship and port agent's name and phone number, I'll have to remember that for next time, I just grabbed the paper with the info on it, but I did program the cell phone company's outside the US customer service number and my inside the US and outside the US phone numbers for my credit card companies I was bringing with me when on my Med cruise and figured I'd just give them my SS# to cancel my card(s) if they were lost/stolen. I usually bring 2 or 3 (leaving the one I used for the onboard account in the cabin safe the entire cruise) because if I had to cancel the onboard account credit card it would be interesting settling the onboard account  |