New Guide Layout feature for Photoshop CC (2014.2)
We've updated guides in the latest release of Photoshop. Now multiple guides can be added at once to generate a layout.
If the Width and Height are left blank, the guides automatically resize to fit the canvas.
The Center Columns option will center align the layout if a specified width has been given for columns.
Guides update quickly on the canvas to give you a preview. The input fields are scrubbable to change the value.
Read more these updates here: http://www.setopacity.com/articles/2014/10/7/guide-updates-for-photoshop-october-2014