FOB or "Free on board" with a named place of shipment is an International Term of Sale that means the seller fulfills his or her obligation to deliver when the goods have reached the named place of shipment. Common shipping terms for over ground transportation include FOB Shipping, also known as FOB origin, and FOB destination. FOB Shipping implies title passes to the buyer upon shipment. FOB Destination implies title passes to the buyer once the goods have safely arrived at the shipping address.

Determining when the risk of loss transfers from the seller to the buyer will be one key in demining where a sale has taken place and if a liability to collect sales tax on freight has attached to your company. At a minimum you will also need to know if your company has nexus with the state in which the sales occurs, if freight is considered as part of the basis of the selling price of the goods being sold and how using a common carrier may impact the point of sale.

The link is to an accounting study on shipping terms: http://simplestudies.com/what-are-fob-shipping-terms.html