Shipping
This attribute provides the specific shipping estimate for the product. This overrides the global shipping settings you defined in your Google Merchant Center settings. There is much more info here, under the shipping tag.

There is a global setting which will draw through all the data from the shipping module per product or you can set it per item as below.

The component asks for the country, region, service and price.

If you leave the country, region and service blank, but put an entry into the price field, it will make a fixed price entry for this product.

The "region" is not used in the UK, Germany or France, so only the USA.

Google accepts multiple entries for this attribute set, one set looks like this

<g:shipping>

<g:country>GB</g:country>
<g:service>Royal Mail</g:service>
<g:price>10.00</g:price>

</g:shipping>

So you could specify many of these sets, each having different costs to different countries for example per product. We are working on a way to add this feature into the Google Base component, that will be user friendly but do the job correctly.

http://www.google.com/support/merchants/bin/answer.py?answer=188494#shipping