Google is ready to unveil a suite of software for mobile phones based on open source technology, backed by some of the largest wireless industry companies in the world.

The company plans to unveil the project today, which is said to incorporate Linux-based software into a mobile platform -- code-named Android -- according to sources familiar with Google's plans. A software development kit for a so called "complete mobile-phone software stack" is believed to be in the works and will be released soon after, the sources said.

Japanese wireless carriers KDDI and NTT DoCoMo are allegedly involved in what will be called the Open Handset Alliance, according to other sources. More than 30 other companies involved in the alliance include names such as Qualcomm, Broadcom, HTC, Intel, Samsung, Motorola, Sprint, and Texas Instruments.

Don't expect to see a Google phone, or Gphone, on store shelves anytime soon though. With so many different players, plans and details could still change. It's unclear when the final version will be released and Google has repeatedly declined to talk about the Gphone or confirm the event.

Persistent rumors of Google's interest in the mobile-phone market have captivated Silicon Valley and the wireless industry for months. Its interest appears to be simple: there are more than a billion mobile phones in the world, and sales show no signs of slowing down.

Mobile phones are just starting to move beyond the stripped-down mobile Internet and join their PC cousins where search and other mobile applications will be essential to the survival kits of any sophisticated mobile phone platform.

Android was the name of a mobile-phone software company acquired by Google in 2005 and led by Andy Rubin, the co-founder of Danger. It was never entirely clear what Android was working on, but it appears to be coming to fruition.

The open-source community appears to be contributing a lot of technology to Android. Google is expected to license Android under the Apache License, Version 2.0, according to sources.

Wind River Systems, a company that specialises in tailoring Linux for embedded devices such as network equipment and mobile phones, is likely to be a key part of the alliance, sources said. The company is expected to play a role in working on a Linux foundation for Google, integrating it with specific hardware, and providing support to phone companies using the software.

A Wind River representative declined to comment Friday on any Google partnership.

Wind River had been fond of its own operating system, VxWorks, but since 2003 Linux has been a top priority for Chief Executive Ken Klein.

Can Google overcome the standards hurdles?
But Linux in mobile phones has been a tough proposition for multicompany consortia over the years. Among those that have tackled the challenge are the Linux Phone Standard (Lips) Forum, the Open Source Developer Labs, the Consumer Electronics Linux Forum (CELF), and most recently, the LiMo Foundation founded in 2006.

The Google group is separate from LiMo, but the two share many members, a potentially beneficial connection which could see Linux-based phone software for Google could dovetail with LiMo's work, providing mobile phone software developers with a unified software foundation.

Mobile phones can't run just any software. Battery life is paramount, and therefore software must be designed to run inside a constrained environment with limited amounts of memory and processing power at its disposal. Linux appeals to phone makers because it is modular, making it easier and relatively cheap to piece together only the technology needed.

Also, phones are complicated compared to PCs. ARM's chip designs are at the heart of almost every mobile phone in the world, but those cores get implemented in very different ways by partners such as Samsung and Texas Instruments; ensuring application compatibility across multiple phones is a difficult undertaking.

The key to Google's software, however, will be how it's accepted by the public. People are drawn to sleek hardware, but they spend the majority of their time working with software. That's where an attachment is formed with a computer, and that attachment is particularly strong with a device you would carry with you everywhere you go. No details were immediately available as to the look and feel of the software.

Word of the pending Google news had reached JumpTap, a competitor to Google in the mobile ads space that is not included in the announcement.

"I'm not sure if it's an industry-supported event or a Google trap" to get developers to write to Google software, said Dan Olschwang, chief executive of JumpTap. "If it is really open source and the mobile-phone manufacturers will adopt it, it will be a major industry-changing event."

Google isn't just looking to expand its ad monetisation technology to new platforms, but also to shake up the telecommunications industry and its "walled garden" approach that limits what handsets, carriers, and services consumers can use, industry experts said.

"Google's stated open-source approach, or open net approach to life, is antithetical to the way cellular carriers look at the world," said Tim Hanlon, an executive vice president at Denuo, a consulting arm of advertising agency Publicis Groupe. Carriers are "loath to separate device from service. They're loath to let third-party applications play on their proprietary network."

If Google succeeds in opening up the industry it will be the biggest thing the search company has done in the last couple of years, said Stephen Arnold, author of The Google Legacy and a new book, Google Version 2.0: The Calculating Predator. "The phone companies "don't understand the business Google is in, and now they're talking to them!"

And the company could very well have a trump card to play, if it follows through on its interest in the 700MHz spectrum auction scheduled for January 2008.

Can Google really be a mobile-software developer, search engine, application house, and wireless carrier? And will people actually want to use that? We might soon find out.

News.com's Stephen Shankland and Elinor Mills contributed to this report.