XCart – ecommerce shopping cart:

    * X-Cart shopping cart is fast. For most web stores there is no need to arrange a dedicated server
    * X-Cart has a W3C-compliant storefront with a CSS-based layout. And it comes with several professional e-commerce design templates
    * AJAX-based components and WYSIWYG editors improve the user experience
    * X-Cart is search engine friendly. You can add meta-tags and define custom titles and URLs for product and category pages, which improves standing of your web store with popular search engines
    * Smarty template engine and simple PHP code make X-Cart flexible and easy to modify without great programming skills and knowledge
    * X-Cart professionals are always ready to help you with any technical answer about the software as well as handle installation & configuration tasks for you
    * X-Cart team offers professional design creation and custom programming services. You can get a unique storefront design and a custom-made functionality to ensure the web store meets your business needs completely

   1.  X-Cart custom development to match your local environment
   2. X-Cart SPAM Protection
   3. Add-on modules and payment methods to fit your business specifics
   4. Professionally performed upgrades
   5. Advanced security issues
   6. High usability issues
   7. Automation of store administration
   8. Your PPC advertizing campaign management and planning
   9. ROI tracking applications
  10. X-Cart Turnkey Solution
  11. Unique design with SEO
  12. X-Cart performance optimization

Zen Cart ecommerce shopping cart: is a free, open source, online store management and shopping cart system, Zen Cart is one of the richly rewarding eCommerce systems that is PHP-based and uses MySQL database and HTML components. The system is apparently a good support for many languages and currencies, and is available for free under the GNU General Public License.
Salient features offered by Zen Cart:

    * Multiple language support
    * Multiple customer modes
    * Unlimited category depth
    * Multiple sales and discounts
    * Multiple display modes
    * XHTML 1.0 compliant template system
    * Unlimited extra pages
    * Multiple ad banner controller

    * Multiple shipping options
    * Multiple payment options
    * Newsletter manager
    * Discount coupons
    * Gift certificates
    * Featured products
    * Quantity discounts
    * PhpBB integration through external module

 Zen Cart Features include:

    * Installation
    * Functionality Customization
    * New Module Development
    * Store Maintenance
    * Installation
    * Design and Design Integration
    * Upgrades
    * Payment System Integration