If you had a nickel for every time you wanted to play hangman or tic-tac-toe but couldn't find a partner, you'd be a millionaire. At least, that's what wireless companies seem to think.

They're counting on cell-phone gaming as the next killer app for mobile commerce.

Four out of five mobile phone users in the U.S. and Western Europe will play mobile games by 2005, according to the market analyst firm Datamonitor. That adds up to 200 million customers and $6 billion in revenue over the next four years, mostly from sponsorships, pay-to-play charges, and subscriptions.

And last week Sony Computer Entertainment, which makes the popular Playstation console, said it had abandoned plans to develop a portable game device because it believed mobile phones would become the platform of choice for wireless gaming.

But if games are the future of the wireless Internet, why would the editors of PC Gamer and Gamespy say they'd hardly heard of it?

What's clear is that mobile gaming is still in its early stages.

Most phone games available today are single-player or turn-based parlor or casino-type games like hangman or roulette, designed to be played in short intervals, usually between 5 and 10 minutes. Several carriers currently carry such games from companies including Digital Bridges, Indiqu, Pogo.com and Unplugged Games.

But as wireless technology advances, mobile gaming companies expect to release more elaborate multiplayer games -- featuring real-time and persistent action, and location-based features.

"At the moment, most developers have the attitude that the cell phone is really simple, and that it's too underpowered for gaming," said Alex Green, vice president of business development for U.K.-based nGame Inc. "There are very few companies taking advantage of the phone's unique advantages as a communication device, that is of course, portable."

NGame, which has over 400,000 registered users in the U.S. and Europe, currently specializes in trading and adventure games such as Alien Fish Exchange and Merchant Princes.

Of course, mobile gaming will have to overcome the age-old chicken-and-egg problem before it can realize the potential that Green envisions.

"It's an interesting concept to play games wirelessly, but the user experience is too limited to have mass-market appeal," said Frederik Liliegren, president of RedJade, a mobile-entertainment content startup funded by Ericsson.

Wireless content, including games, will remain irrelevant unless wireless technology advances and makes m-commerce feasible. But m-commerce will never become feasible, as long as wireless content remains irrelevant, Liliegren said.

Most phone games available now are free, as long as your service plan includes free minutes. But carriers hope to introduce pay-to-play or subscription charges for games soon.

"People using a mobile phone expect to pay," said Brian Baglow, a spokesman for Digital Bridges. "You already expect to pay for air time. That's one big difference from the fixed Internet, where the expectation is that you can get anything for free."

Carriers point to Japan, where 60 percent of the content viewed by NTT DoCoMo's 19 million i-mode users falls into the entertainment category. That includes everything from ring-tone melodies to games, some of which users pay for.

Next-generation wireless networks should make subscription and pay-to-play billing more feasible. Instead of paying for air time, users will pay for the volume of content they download, with extra charges applied for premium content such as games.

Logistics aside, skeptics say that consumer psychology in the West may be dramatically different from that in Japan. Just because i-mode users have embraced mobile entertainment content, they say, doesn't mean Americans and Europeans will, too.

"There are very few applications of i-mode that are going to transfer well in the U.S.," said one anonymous wireless company spokesman. "Americans are much more pragmatically focused. Maybe stock quotes or news alerts, but I don't think there's a huge market for cutesy icons or games."

Mobile gaming companies shrug off the skeptics, saying that to try a game once is to get hooked.

"Come and try this, that's all we're asking," Baglow said. "If you don't like it, fine."