SEATTLE — Amazon.com Inc.'s brick-and-mortar competitors have yet another reason to fear the Web: a new service that lets shoppers compare prices and buy things with a few quick taps on their cell phones.

Amazon TextBuyIt, which launched late Tuesday, lets people text the name of a product, its description or its UPC or ISBN to 262966 (that's "Amazon" on the keypad) from anywhere their cell phones work _ including from inside physical stores.

If Amazon stocks matching items, the service returns two results at a time. Shoppers can immediately buy one of the first two the selections by texting back the number "1" or "2," or they can ask for more by texting the letter "M."

New TextBuyIt customers will be prompted to enter the e-mail address associated with their existing Amazon account plus a shipping zip code. The service then calls them and walks through the checkout process using an automated voice system. Shoppers get confirmation by text message and e-mail.

From there, the customers can check on order status on Amazon's Web site.

Howard Gefen, director of Amazon mobile payments, would not directly answer when asked if the service is meant to extend Amazon's reach by poaching customers browsing at bookstores or big-box electronics retailers.

"We think this is a great experience. We think they'll use the product...wherever they happen to be," he said.