1. Using one of the custom shapes in Photoshop, draw a custom shape onto a transparent background. Make sure that it's one colour. In this case, I'm going to draw a heart.

2. Using the wand tool, , click on your shape. Right click and pick 'Select Inverse'.

3. Press Q on your keyboard. That should have entered Quick Mask Mode, and your shape should be a nice red colour now.

4. Go to Filter >> Pixellate >> Colour Halftone. I adjusted the max radius to 20 pixels, and pressed Ctrl + F a few times. This is what I got when I was satisfied.

5. Press Q to exit Quick Mask Mode. Right click and pick 'Select Inverse'.

6. Make a new layer, and using the fill tool, , fill in the selected area. Deselect everything. This is what it looks like for me now.

7. Now all you have to do is delete the layer underneath, and this is what you get.

Neat, isn't it? The best thing is, it works for all sizes and shapes. You can make your own brushes with it, use it on your layouts, etc. Although now that the 'secret' is out in the open, I suspect many people are going to be making the same brushes now. ^-^;;