Google announced it would release an free open-source operating system based on its Chrome browser. Chrome OS will available for purchase on netbooks in the middle of 2010. Netbooks are low-cost notebook PCs designed for internet surfing and other web-based applications. Google Chrome OS will be aimed initially at small & low-cost netbooks, but will eventually be used on all personal computers as well.
This is what Google's official announcement says:
Google Chrome OS is an open source, lightweight operating system that will initially be targeted at netbooks. Later this year we will open-source its code, and netbooks running Google Chrome OS will be available for consumers in the second half of 2010. Because we're already talking to partners about the project, and we'll soon be working with the open source community, we wanted to share our vision now so everyone understands what we are trying to achieve.