Google on Monday announced a widely expected open-development platform for mobile devices backed by industry heavyweights like T-Mobile, HTC, Qualcomm, and Motorola that could shake the wireless market to its core by simplifying and reducing the cost of developing mobile applications.

[ Analysis: Google Android joins an already crowded list of options ]

The platform, called Android, has been developed by Google and others as part of the Open Handset Alliance, which has over 30 partners supporting it. The goal of this ambitious initiative is to spur innovation in the mobile space and accelerate improvements in how people use the Web via cell phones.

As previously reported by IDG News Service, the open-source platform will have a complete set of components, including an operating system, middleware stack, customizable user interface and applications.

The first Android-based phones should hit the market in the second half of 2008. The platform will be made available under an open-source license that will give a lot of flexibility to those who adopt it to modify its components and design services and products, Google said.

The alliance will release an "early access" software development kit next week to provide developers with the tools necessary to create applications for the platform, Google said.

"Our vision is that the powerful platform we're unveiling will power thousands of different phone models." Google Chairman and CEO Eric Schmidt said in a statement.

Other founding members of the alliance include Broadcom, eBay, China Mobile, Intel, LG Electronics, NTT DoCoMo, Nvidia, Samsung, Sprint Nextel, Telecom Italia, Telefonica, Texas Instruments, and Wind River.

Noticeably absent from the list is traditional Google ally Apple, whose popular iPhone might see its innovation lead cut sooner than expected thanks to this Google effort.

In a press conference Monday, Google CEO Eric Schmidt said that Android will "create a whole new mobile experience for users with new applications and new capabilities that we couldn't imagine today."

There are about 3 billion mobile users worldwide, so improving their access to Internet services and applications fits in with Google's core mission, he said.

Making it easier for people to access Google's search engines and other online services via mobile devices is key to the company, which must extend its advertising business to the wireless world.

While a nascent market, mobile advertising is expected to balloon in coming years. According to Opus Research, mobile advertising spending in North America and Western Europe will reach a combined $5.08 billion by 2012, up from an estimated $106.8 million at the end of this year. This represents a compound annual growth rate of 116 percent.

Opus Research, which released the forecast last week, said that improving the mobile user experience will prompt more people to spend more time using the Internet via their cell phones. This in turn will fuel ad revenue growth.

Calling Android "the first truly open and comprehensive platform for mobile devices," Schmidt said Google hopes it will power "thousands" of different mobile phones, including, if one were ever to be built, a Google-branded "Gphone."

Android, which a Google spokesman said will be completely free, will be made available under the Android Apache v2 license, which Schmidt described as "the most liberal open-source license given to mobile operators or anyone ever."

"This platform fundamentally means a new level of innovation in many ways: All kinds of new applications that have never been possible in any other mobile device and the acceleration of ways in which these applications are made available to consumers," Schdmit said.

Innovation in the mobile market has been hampered by a lack of collaboration and of technical standards and by the high costs of development and difficulties in distribution, he said.