After months of speculation about its ambitions in mobile telephony, Google on Monday revealed its plans... would not include a so-called gPhone.

Instead of hardware, the search conglomerate introduced Android, a Linux-based open development software platform for mobile phones, and a broad alliance of technology companies dedicated to building applications and devices with Google's software.

"This partnership will help unleash the potential of mobile technology for billions of users around the world," said Google chairman and chief executive Eric Schmidt in a statement. "A fresh approach to fostering innovation in the mobile industry will help shape a new computing environment that will change the way people access and share information in the future. Today's announcement is more ambitious than any single 'Google Phone' that the press has been speculating about over the past few weeks. Our vision is that the powerful platform we're unveiling will power thousands of different phone models."

Google's ambition is nothing less than prying the telecom industry open and merging it with the Internet. "The openness of the Internet is starting to impact the relatively closed environment of the mobile handset makers," said Mark Kirstein, founder and CEO of MultiMedia Intelligence, a technology market research firm.

"Android is the first truly open and comprehensive platform for mobile devices," said Andy Rubin, Google's director of mobile platforms, in a blog post. "It includes an operating system, user interface, and applications -- all of the software to run a mobile phone, but without the proprietary obstacles that have hindered mobile innovation. We have developed Android in cooperation with the Open Handset Alliance (OHA), which consists of more than 30 technology and mobile leaders including Motorola, Qualcomm, HTC, and T-Mobile."

Google said that the OHA plans to release a software development kit next week. Ethan Beard, director of new business development at Google, who helped set up the partnerships behind the OHA, said that the SDK would rely on the Apache 2.0 license, which allows developers to create proprietary applications on top of the Android platform without being forced to make their application code publicly available.

Google's "open," then, is open with an asterisk. But it's certainly more open than other phone platforms to date.

Android also promises to open a new revenue stream from mobile advertising, which to date has been more of a trickle. "Mobile advertising is still a tiny little industry, but this is a major development," Kirstein said.

Google has a long list of partners for this alliance: Aplix, Ascender, Audience, Broadcom, China Mobile, eBay, Esmertec, HTC, Intel, KDDI, LivingImage, LG, Marvell, Motorola, NMS Communications, Noser, NTT DoCoMo, Nuance, Nvidia, PacketVideo, Qualcomm, Samsung, SiRF, SkyPop, SONiVOX, Sprint Nextel, Synaptics, The Astonishing Tribe, Telecom Italia, Telefonica, Texas Instruments, T-Mobile, and Wind River.

But it's also worth noting who's absent from the list: Apple, AT&T, Microsoft, Nokia, Palm, Research in Motion, Symbian, and Verizon.