I live in Florida and this is something that I will have to tackle sometime too. Although my UberCart store is on hold as I wait and hope to find out how to handle Freight Shipping (hint, hint)

The way I handle the discretionary sales tax in another system (Lotus Notes) was by purchasing a cheap zip code list. It was a CSV file that had zipcode in one column and city, county, etc in the others. I would simply match the ZIPCODE and then pull the county name from the other column.

When you sign up to collect tax in FL, one of the documents (Doc. DR-15DSS) has a list of all the FL counties (aporx. 50) and their discretionary tax amount. So simply compare the zip>county to the county list, find the discretionary tax amount and add 6% to it. Their are a lot of counties that do not have a discretionary tax, so that makes it a little simpler.

The only other things to watch out for are changing zip codes and discretionary tax amounts.

Now I had assumed that UC would correctly add the tax amount for the FL county, am I wrong?