Recently Google announced 28 Chrome themes available to Google Chrome 3.0 Beta,Google Chrome 3.0 Developer Preview
How to install the theme
First visit the theme gallery, choose your desired theme click on Apply Theme. Save the .crx file and Chrome will automatically load that theme for you and also offers you an option to go to defaulttheme. There is no option to preview the theme before installing.
How to uninstall the theme
If you want to uninstall a particular theme, in the address bar type chrome://extensions/ and hit Enter.
Chrome will show you all the installed extension and you can uninstall any theme you want by simply clicking the Uninstall button below the theme name.