Would it be practical to develop a FL sales tax module? Like I had said in my previous post, you can purchase a CSV file with all zip codes in the US. This file can be striped down into two columns - column one would be all FL zip codes and column two would be the county that that zip is in.

Using this data, how easy would it be to make a module that would do the lookup? I have no real experience in Drupal module development, so I don't really know what would be involved. Would you put the zip/county data in an external file, in the module, or in the drupal database?