I have not sailed on the Sky since 2000, when wireless was in its infancy and not available on any ship, but since then I have sailed on five times on four of their other ships and have found that their wifi access is some of the best at sea. On Dawn, Star, Jewel and Jade it was available in the stateroom. I would "believe" that it will be the same on the Sky. Regardless it will be available in various hot spots around the ship so you won't be without connectivity.
Have a great cruise,