Wal-Mart Stores Inc., the world's largest retailer, said on Tuesday that it has seen strong results from its service that allows customers to order products on its Web site and have them shipped to a local Wal-Mart store for free.

The Site to Store service is now available at more than 3,300 U.S. stores. Wal-Mart said customers have saved more than $5 million in shipping fees since it launched the service in March.

(Reporting by Jessica Wohl)