I was playing around in Photoshop for a change :) I made some spatter type brushes. They simulate the effects you would get with using a toothbrush and paint, and rubbing your finger along the bristles. They aren't perfect, but it's Photoshop and it has it's limitations with brushes sometimes. I love Photoshop and the brushes, but yeah, I wish they had the ability of Illustrator brushes, that would be awesome!
Anyway, here's a preview (click on the image to get a bigger version):
Download link has expired.
If you like them, you can download them here. I made them in CS3 so have no idea if they work in older versions, as I have no way to check.