Today I submitted a contribution to the open source e-commerce project called Open Cart. My contribution is an XML product feed generator script that is compatible with Google Base. It requires not modification of the Open Cart core and is a simple upload installation. This script automatically generates a Google Base compatible product feed and it can be modified very easily by any programmer.
If you would like to see my contribution just visit the Open Cart extensions site here:
http://www.opencart.com/index.php?route=extension/extension/info&extension_id=965&filter_search=Simple%20Product%20Feed&sort=e.date_modified&order=DESC