Print on demand (POD), also called publish on demand, offers authors the option for printing their books once an order has been received. POD had the advantage of minimal financial risk as there is no inventory required, no outlaying money for printing books that may take some time to sell.
Tip #1: Be aware that with POD, the cost per book is a lot higher than with an offset press.
Tip #2: International authors who want to sell their books to the U.S. market should use http://www.ingramspark.com/.