NEW YORK (AP) — Amazon says it is teaming up with the U.S. Postal Service to deliver packages on Sundays. The Seattle company says Sunday delivery will be available to Amazon Prime members in the New York and Los Angeles metropolitan areas at first. Amazon and the Postal Service plan to roll out service to "a large portion of the U.S. population" next year, including Dallas, Houston, New Orleans, and Phoenix. Amazon Prime membership costs $79 a year. Members get free two-day shipping on millions of items on the site and access to Amazon's TV and movie streaming service. Amazon.com Inc. says members can add eligible items to their carts and will see Sunday delivery at checkout when it is available. Shares of Amazon slipped 81 cents to $349.50 in premarket trading.