LAS VEGAS — Retailers and wireless companies are again dialing for dollars with cell phones.

Amazon.com, which revolutionized shopping on the Internet, this month introduced a service that lets users buy goods using simple text messages from their mobile phones.

Users who set up an account with Amazon's new "TextBuyIt" service can send a text message on their cell phone to Amazon with the name, bar code or ISBN code of the product they want to buy. Amazon automatically searches the Web and its warehouses for the product and replies with a detailed list of items, prices and features.

To buy, a user simply presses a number corresponding to the wanted item, and the product — and the bill — is automatically sent to their home.

"Any Amazon.com customer can now use any mobile device to shop and buy from Amazon.com, at any time, anywhere they are," Howard Gefen, director of Amazon Mobile Payments, said in a statement.

One of the biggest ways a consumer might use a cell phone for shopping, however, might involve not purchasing goods, but comparing prices.

Wednesday at the CTIA Wireless industry trade show, Internet search company Yahoo! showed off a new cell-phone search engine it plans to roll out this summer that will also make it easier for users to get instant information on products and services while on the go.

These new services mean that a customer with a Web-enabled cell phone will be able to walk into a Best Buy, for instance, and instantly compare the store's prices for a TV with those at an online retailer. If Best Buy isn't willing to match the Amazon price, the customer could buy online with a cell phone on the spot.

Of course this isn't the first time Amazon or other retailers have tried to turn the cell phone into a shopping mall.

Retailers and wireless companies have been pushing "m-commerce" in various forms almost since the advent of the mobile phone. At CTIA, numerous companies are showing off all sorts of m-commerce offerings.

So far, though, most attempts to get consumers to shop with their cell phones have had scant success, at least in the United States. Even at CTIA, when attendees at a panel discussion on m-commerce were asked if they've ever had a pleasant experience with buying goods with their cell phones, almost nobody raised a hand.

What's reviving interest in m-commerce, though, is better technology and growing acceptance by both consumers and retailers.