TAX

• http://www.usps.gov/ncsc/ provides a service that returns the county and complete zip code for an address which could be used in tax calculations.
• http://www2.taxware.com/taxcalc/index.asp provides a online tax calculator that will calculate exact sales taxes for free ten times after the merchant has filled out setup information. This could possibly be used to provide information for tax estimating by A) setting up an account for each store and B) doing full scale processing.