I came across guideguide recently and I’ve been playing with it – I used it to create my latest template – the Mosaic Tile – I set my rows, columns and gutters, created and filled the first box, then went about duplicating and placing based on the guides for an almost perfect spacing. While this is still the beta version, it works pretty well for basic guidelines and I’m anxiously waiting for his future updates to add a ‘clear all guides’ function, saving guide presets, and hopefully a more advanced version of placing guides. I am still searching for that offset function that I love so much in AutoCAD! But for now, if you have Photoshop CS4 or CS5 you should check it out and see what guideguide can do for you!