In Google words, “Operating Systems on which browsers run are designed in the era when there is no web. Google Chrome OS is an attempt to rethink what OS should be”.

What is Google Chrome OS:

Google Chrome OS is an open source, light weight operating system. Speed, simplicity and security are key aspects of Google Chrome OS with minimal user interface.
Chrome OS will have completely redesigned security architecture to protect users from viruses, malware and security updates.
It will run on both x86 as well as ARM Chips.

Why google is releasing one more OS, when it is having Android already in its lap. As per google Android was designed from begining to work across a variety of devices from phones to settopboxes to netbooks and Google Chrome is created for people who spent more time on web and is being designed to power computers ranging from small netbooks to full-size desktop systems.

We need to wait till 2010 second half for Chrome OS to be available on netbooks.