Unless they've changed things since I live there in 2003 Florida requires sales tax to be collected only on purchases made in the state that are delivering products to a buyer in the state. Also, the tax you charge to Florida buyers will be the tax rate for your county so in Orange County the rate was 6% (just the state rate) but in Seminole County the rate was 7% (because the county added 1%).

Check with your local tax collector's office for the exact requirements.

In Ubercart you'll setup the tax under Adminter > Store Administration > Configuration > Tax rates and settings

Then go to Site Building > Workflow-ng and click the Label Florida for the configuration that is setup and add a new condition that checks the Order Zone about whether it is in Florida.

That should take care of things. Again, double check with your local tax collector about what is taxable.