After promising to ship its browser-based Chrome OS by the end of 2010, Google today admitted it wouldn't meet that schedule and will instead target mid-2011. The OS will be made available on netbook-class hardware, running Intel Atom microprocessors, Google said, as well as other device types.

"In the first half of next year, Chrome notebooks will be available for sale from Acer and Samsung, \\[and\\] more manufacturers will follow," Google VP Linus Upson wrote in a blog post. "Also, Chrome OS is designed to work across a wide range of screen sizes and form factors, enabling our partners to deliver computing devices beyond notebooks."

To jumpstart Chrome OS development, Google has announced a Chrome OS pilot program in which potential users can sign up to gain early access to nonbranded netbook/notebook computers running a beta version of the new OS. These devices feature a 12.1" screen, a full-sized keyboard, integrated Verizon 3G and 802.11n networking, and a web cam, Google says.

(It's unclear whether the devices are technically notebooks or netbooks; the 12" screen suggests notebook, but I believe it's running on an Atom processor, which is distinctly netbook-class. Regardless, they very closely resemble a black Apple MacBook.)

Based on a demo of the new system, Chrome OS looks and works much like the Chrome web browser in full-screen mode. You log on to the system with your Google account and then access web apps as if they were local applications; Gmail, YouTube, The New York Times, NPR, Google Maps, and other web apps could be seen during this demo. A guest mode is available, too, for browsing privately without signing in. Google promises 10-second boot times, instant resume, and, on the prototype hardware, eight-hour battery life and eight-hour standby.

Google also announced a new Chrome Web Store that will help users discover new web apps. Similar to Apple's iTunes Store, the Chrome Web Store is available from directly within the Chrome OS web browser. (It's also available publicly here.) This store provides a number of free and, interestingly, paid web apps.