Google Offers Native Microsoft Word and Excel File Editing with New Chrome OS Release
To access the feature, your Chrome OS device has to be on the developer channel, If it is, just type "chrome://flags" (without the quotes) into the address bar, scroll down to "Enable document editing," and click "Enable." Once you make the change and reboot the machine, you'll be able to edit Word and Excel documents.
The technology to do this is based on Google's QuickOffice acquisition in June 2012. While this is an experimental feature at the moment, it certainly appears Google is working towards adding official support for Word and Excel, and probably PowerPoint too, by the end of the year. The next step is for the feature to make its way out of the dev channel and into beta, and then make the jump to the stable channel.
In other words, hang tight Chromebook owners, QuickOffice on Chrome OS is coming.