Google Chrome OS will be an open source, lightweight operating system targeted at netbooks initially.
Google is planning on releasing the code later on this year and we should see netbooks running Google Chrome OS emerging in the latter part of next year.
The new operating system sounds very promising and the areas where Google is really focussing its efforts marry up well with most users complaints with existing operating systems, such as speed, simplicity and security. As a netbook owner myself (Acer Aspire One running Linux), I'll be watching this development with interest. In the post on the official Google blog Google states:
We're designing the OS to be fast and lightweight, to start up and get you onto the web in a few seconds. The user interface is minimal to stay out of your way, and most of the user experience takes place on the web. And as we did for the Google Chrome browser, we are going back to the basics and completely redesigning the underlying security architecture of the OS so that users don't have to deal with viruses, malware and security updates. It should just work.