I'm looking to travel to Tampa in July. I found this site has some information. They mention a few of the hotels have a "Book With Confidence" which means that " if you arrive to find our pristine beaches affected by the oil spill in any way, your first night is 100% on us---taxes and resort fees included."
Oil Spill Update | St. Petersburg Clearwater vacation and travel
But just because the hotel is free doesn't mean your trip is ruined. If you can no longer goto the beaches, the airfare is non-refundable, etc... Especially if you would rather go somewhere else!