Some of the best deals for hotels can be obtained through Priceline or Hotwire, and i have used them for every pre-cruise stay. I recently received the Hyatt in downtown Miami for $27/nite!!
Here's a website that shows the hotels people have received so that others will have a better idea of what hotel they might get; they will also help advise you if you're never used either service before. There is also a section in the Florida area specifically designed for cruise passengers.... discusses what zones to use, how much cab fare, etc.