The iPhone is built for communication, but so far most of the games made for it have been a solitary experience. Demiforce, a start-up with one hit iPhone game to date, wants to change all that.

The San Francisco company is preparing to launch Onyx Online, an online gaming technology for the iPhone. The aim is make it easy for iPhone developers to create games that offer the same kind of all-encompassing multiplayer experience as Microsoft’s Xbox Live service on the Xbox 360, said Steve Demeter, managing director of Demiforce.

Demiforce is signing up dozens of game developers who will use its application programming interface (API) and framework to deliver basic multiplayer functions. That includes a lobby where gamers can gather, leaderboards for high scorers, achievements that gamers can brag about, and simultaneous online multiplayer play. That’s sounds like a complicated undertaking, particularly for a five-person company.

But Demeter said he has already done a dry run with a hit game, Trism, which sold 250,000 copies at $4.99 a piece in its first two months on Apple’s AppStore. The company was formed to do coding for hire in January, 2006. Then it switched gears to develop iPhone applications. In July, it released Trism with the opening of the App Store. Now there are thousands of games on the iPhone.

It remains to be seen what kinds of games and how many simultaneous players can be supported. Demeter said the only real limit is the processing power of the iPhone itself. That is, it is not a software or network issue. Demeter says it would be challenging to do a massively multiplayer online game, where players stay in a rich game world for many hours at a time. That is more like an infrastructure issue, he said. But he said it is not impossible.

But Demeter said that he was surprised that neither Apple or anyone else tried to build the equivalent of Xbox Live, which has morphed into a social network for gamers and enables basic multiplayer capability.

“Right now, you play a game and you’re done,” he said. “Not a lot has been done to retain the experience for the next time you play as you can with the consoles.”

There are competitors who will go their own way. Zynga has launched Live Poker for the iPhone using its own technology. And Aurora Feint II recently launched as an asynchronous multiplayer experience for the iPhone. Other multiplayer games: Apple’s own Txas Hold’em, Gameloft’s Uno and Asphalt 4, and Scrabble from¬†Electronic Arts.

Mark Pincus, chief executive of Zynga, doesn’t know about Onyx Online in particular. He believes that social gaming on the iPhone has a great future. But he is skeptical that the platform is ready yet to support fast action online play with the same kind of quality that you see on the game consoles. Slow-moving games without huge animation or network demands such as poker are more likely to succeed in the meantime, he said. He noted that there are more than 100,000 daily players for the iPhone poker game just three weeks after the launch. That’s far faster than the poker game took off on MySpace.

While Apple hasn’t addressed making online gaming easy for developers, rival Nokia has put a lot of emphasis on online play with the N-Gage game platform. That’s because online game services keep gamers coming back, generating minute usage for carriers and more game sales. A lot of players only play multiplayer games because it means they have a fresh experience every time and don’t have to face stupid artificial intelligence in computer opponents.

Apple hasn’t moved toward doing its own online game service and has expressed enthusiasm for Demiforce’s efforts, Demeter (pictured left) said. Demiforce’s code will be available for others to use to more conveniently make online games that have the ability to create gamer logins, communities, forums, tournaments and other multiplayer functions. Demiforce is working on five Onyx-enabled games on its own.

Demeter said the company is going to make some announcements soon and is getting ready for a beta launch with a lot of games already in the pipeline at independent developers. Developers can use Onyx Online for free and gamers can access the network free of charge. The company has revenue models in place, but Demeter said he will describe those later.

“We view our own role as very open,” he said. “We want to capture the momentum of the App Store. It’s a meritocracy for the first time now. You don’t have to work with a big developer.”

He said that Onyx Online forums will make it easier for people to talk to others and find the games that they want among the 10,000 apps on the iPhone. In 2009, Demiforce hopes to take the technology to the Google Android cell phone software platform and the BlackBerry. He said that players should be able to take the identities they create on the iPhone and then migrate them to other phones.

One of the other benefits of the online service is the ability to analyze and measure user behavior within the games, Demeter said. That can be shared on a high level with advertisers, but Demeter said the company will make sure it has proper privacy controls in place.

Demiforce is self-funded to date but it is in talks to raise more money. Demeter, 30, said he has been making games since he was in college in the 1990s.