NEW YORK (Reuters)—Imagine being able to pay for a song on the jukebox, buy a bag of groceries or gain admission to a sports arena by simply waving your phone by a machine.

With consumers in Asia and Europe already using their mobile phones to pay for soda and parking fees, the long discussed concept of the wireless wallet could be slowly creeping closer to reality in the United States.

In countries such as Sweden, Ireland and the United Kingdom drivers can avoid putting coins in a parking meter by simply sending a text message on their mobile phone.

About two million customers of Japan's NTT DoCoMo Inc. can already use mobile phones with built-in debit cards to pay about 20,000 merchants such as restaurants and supermarkets.

DoCoMo, which U.S. telephone carriers often look to for inspiration for new services, also plans for customers to use their phones in place of train tickets. It also invested in a credit card company as part of its bet on mobile commerce.

U.S. companies have been quiet about mobile commerce since hype about wireless wallets was deflated when the dot.com bubble burst in 2000. Many are still skeptical, but some are warming to the idea again amid U.S. and overseas developments.

"The (mobile commerce) discussion has more validity now. The technology and the business models are evolving," said Chris Bierbaum a business development executive at Sprint, the No. 3 U.S. operator.

The popularity of music ringtones is one sign consumers are ready to use phones for buying more than calls. Music labels now see wireless as a key market after U.S. consumers spent $223 million on ringtones in 2004 according to Yankee Group.

And as phones—being built with everything from video players to cameras—add even more features, soon the music industry may not be alone in seeing wireless as a lucrative alternative market to sell their products.

"You will continue to see more and more industries come to that conclusion," said Peter Ritcher chief financial officer of Cingular Wireless, the No. 1 U.S. mobile service.

Purveyors of everything from fast food to movie tickets may be next to jump on the wireless bandwagon by way of so-called contactless payment cards that can be waved at a sensor rather than swiped through a sales terminal, one executive said.

These cards are issued by U.S. bank J.P. Morgan Chase & Co and Randy Vandebwong1rhoff, executive director of the Smart Card Alliance said multiple banks plan tests this year.McDonald's Corp. is expect to support the cards and convenience store 7-Eleven Inc. plans to accept them in all its 5,300 U.S. stores by early 2006.

Motorola Inc., the world's second biggest phone maker, is doing tests with MasterCard and it expects its phones to support credit card payments in 2006.

Sprint's Bierbaum believes that once contactless payment cards are popular it will make sense to put them in phones.

"Once they've changed the habit to waving their credit card past a reader instead of swiping it, you'll see the migration to wireless," he said. Wallet phones could help client loyalty by giving consumers a reason to keep phones longer, he said.

Along with Philips and other companies Motorola is also working on a technology that would have consumers waving their phones at posters or ads to read a Web address, where the user could then buy the goods advertised on the poster.

Some analysts question whether this technology, known as near field communications, will catch on as it requires an extra chip in phones and widespread acceptance by advertisers.

In the meantime Sprint customers can buy goods by logging onto the Web on their phones. Sprint plans to offer to keep customer credit card details in a safe place on its network to make these transactions more convenient.

Yankee analyst Adam Zawel forecast mobile commerce transactions worth over $1.2 billion in Europe in 2009, up from $243 million in 2004 while transactions in Asia will increase to $1.7 billion in 2009 up from $370 million in 2004.

He is not yet convinced mobile commerce will take off in the United States but he said it could appeal to organizations including Major League Baseball, which looks to new technologies for quicker ways to get fans into baseball parks.

"If it gets to the point where it's easier to pull out our phone than to pull out cash to pay then consumers will do it," Zawell said.