We provide a number of ways to integrate the products from an e-commerce cart into ShopTab. We support CSV, XML and Google Product Search file formats. While we don't have a specific native integration for Zen Cart there is a add-on available for Zen Cart that allows for the creation of a CSV file via an Excel export. This export will allow for the direct upload of the products into ShopTab.
Zen Cart add-on: http://www.zen-cart.com/downloads.php?do=file&id=1201
Once you have the add-on set-up it will create a file that you can make it in the format that we need for ShopTab upload. The required CSV format for ShopTab upload is below.