usually cell phones don't work at sea, but as you are often close to shore in Alaska, they might even work while the ship is at sea. There should be no problems in port, however.
Concerning film, I understand that the latest post Sept. 11th scanners indeed might harm them so might be a good idea to use protective wrappers. I always tell the security staff about this so they hopefully won't consider me suspicious.
Enjoy your cruise!