Usually, dealing with Photoshop grids is causing a large headache and you need to have nerves of steel (at least this is happening to me). But, it doesn’t necessarily needs to be that way. With GuideGuide, dealing with Photoshop grids has never been easier. Pixel columns, rows, midpoints and baselines can now be created based on your document or marquee with just a click. Frequently used grids can be saved for later use, and they can have multiple measurements.
But, the best thing about this Photoshop grid plugin is that its free. Also there are download versions for both CS4 and CS5 Photoshop versions. To see more about this wonderful Photoshop grid plugin, Smashing Magazine has wrote an article about GuideGuide.
On GuideGuide website there are installation steps, so grab the plugin now.
Free Photoshop grid plugin – GuideGuide