The Google Merchant XML feed is accessible via the root level page /GoogleShopping.aspx. This page generates an XML feed based on all of the available (active, visible, public access) products on the site.
To setup the feed:
1 - Go to www.google.com/merchants and sign in using your Google account.
2 - Click the “Data feeds” link and then “New Data feed” or “New Test Data Feed”.
3 - You can setup a schedule for Google to pick up the latest product details from your site by editing a feed. This schedule also allows you to force a fetch on the data so you can test that everything is working as expected.