From DisneyCruise.com…
Kids ages 17 and under sail FREE on most 6-night and 8-night Disney Cruise Line sailings from Galveston from January 4, 2013 to March 1, 2013! To take advantage of this offer, kids must travel with 2 full-fare Guests in the same stateroom in categories 4A to 11B.
Government Taxes and Fees are not included and are as follows: $52 per person for 6-night Caribbean cruises, $66 per person for 8-night Caribbean cruises and $84 per person for 8-night Bahamian cruises (subject to change).The number of staterooms allocated for this offer is limited. See Important Details.
Be sure to use booking code “KFO”