Symbian's decision to make its source code freely available tips the scales in favor of open-source software in smartphones and could make it harder for Microsoft, and even other open-source platforms like Google's Android and Linux, to compete.

On Tuesday, companies including Nokia, Motorola, NTT DoCoMo, LG Electronics, Samsung, Sony Ericsson, AT&T, Texas Instruments, STMicroelectronics and Vodafone announced that they will work together to make the Symbian OS open source. They will offer it under a royalty-free license to members of a new nonprofit group called the Symbian Foundation.

Symbian is used in about 60 percent of the world's smartphones, which means that open-source software will soon drive the majority of those devices. The proprietary model behind mobile operating systems from Microsoft, Research In Motion and Apple, then, will for the first time be in the minority.

Symbian will become the biggest, but not the only, open-source game in town. Others include the LiMo Foundation, which is working on a mobile Linux-based operating system, and Google's Android, also an open Linux-based OS.

While those projects have been in the works for some time, the Symbian effort could have an advantage because of the decade of growth and development behind it. "It is nearly always easier to start from something you know and change it (Symbian), then to start from scratch (Android)," wrote Jack Gold, analyst with J. Gold Associates, in a commentary about the announcement.

Mary McDowell, Nokia's chief development officer, agreed. "If you look at the assets being contributed to the [Symbian] Foundation, we're talking about a platform with 200 million users, 10 years of development, support from multiple shipping vendors and operators ready today," she said. "As you've seen with some of the new entrants, that's sometimes a hard thing."

She may have been referring to a report on Tuesday that Google's Android project is progressing more slowly than expected, due in part to challenges involved with working with mobile operators. Google is running up against the same difficulties that any new entrant would in developing a new mobile operating system.

In addition, Google faces one of the same challenges that many say has held back Symbian. Even though Symbian powers the bulk of smartphones around the world, it has failed to become an industry standard due in large part to Nokia's perceived control of the software. The vast majority of phones running Symbian come from Nokia, which has made some other handset makers reluctant to license the software because they feel like they would be licensing it from their biggest competitor. Google faces a similar problem in that it's perceived to be driving the development of Android, rather then taking a more community approach.