960 Grid System

http://960.gs/

http://www.tutorial9.net/photoshop/design-a-clean-web-layout-with-the-960-grid/

http://speckyboy.com/2010/09/06/modern-ui-and-layout-tutorials-for-photoshop/

http://speckyboy.com/2010/07/23/40-professional-and-detailed-web-layout-psd-templates/