http://epicgames.com/community/2012.....o-epic-friday/

This is a free tool made by programmers at Epic Games for generating perspective grids and exporting them as photoshop layers, OR to use to find Perspective in an existing images if you wish to sind out the vanishing points. Free and easy to use, and very useful. Enjoy!

Here is how to use it.

http://www.ctrlpaint.com/perspective-grid-utility/

(This is a clean link I checked it and the tool works)

Scott