Web pages & Widgets?

I am creating a simple website that has several complicated components. The website is a retail website that offers a range of products to a specific geographic area.

 I need to know if there is an add-on that I can set into a Foundation stack that will accept the input of a Zip code and return one of two message telling the site visitor if we can or not deliver to their area. I have the ECWID add-on and it works fine. However I need to be able to provide the information before the visitor enters the store so that they don't waste their time.