Or, pick a couple of hotels you are interested and call them. Ask if they have shuttle service available. If you are trying to save money by being "walking distance" away, You may not save much over a further distance hotel being less money and getting a cab ride to the pier.
I have not left out of Ft Lauderdale, but even though the holiday inn Port of Miami is "right across the street" from the cruise piers, to walk from the hotel to the ships is still 2 miles...
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise, Magic 1/14
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013