Create Grid Patterns Easily — Modular Grid Pattern

Modular Grid Pattern is a web application for creating grid patterns for Phoshop, GIMP, Expression Design and other apps. The app features a number of options for customizing the grid; furthermore, it offers downloading the resulting pattern in three sorts of files: .pat, .png and the transparency mask format.

This is a great tool for quickly creating an experimental grid to start designing things ASAP.