Windows/Mac/Linux: The official, actually-made-by-Google Chrome OS won't hit netbooks until late 2010, but you can try out a custom-built Linux distribution that's somewhat stripped down and puts Google's browser at the centre of everything.
"Chrome OS" was built using SUSE Studio, a distribution and virtual appliance builder spawned from the OpenSUSE Linux distribution. It loads up with a Chrome icon, uses built-in webapp links to Google Calendar, Gmail and other Google services as apps, and carries a copy of OpenOffice, just in case you need some straight-up desktop editing done. Most importantly, it holds the latest development copy of Google Chrome inside, along with a pre-built Flash plug-in.
You can grab an ISO image to install Chrome OS to your disk, but most folks will probably want to try out one of the virtual images, pre-built and ready for VirtualBox or VMware. Our beginner's guide to VirtualBox should get beginners started on Windows or Linux machines with Virtualbox. The direct download wasn't working as of this post, but a BitTorrent link posted in the Downloads section of Chrome OS was fairly speedy.
"Chrome OS" is a free download, runs as a bootable ISO on any system or as a virtual image. Tell us what you think of this early stab at a fan-made Chrome OS in the comments.
Chrome OS [Google Code]