http://www.photoshopbrushes.com/ = Concrete, distress and blood brushes.
http://www.misprintedtype.com/v3/goodies.php = Distressed photo brushes.
I found that by using the distress brushes and painting one click black on a layer, then one click white on a separate layer, then offsetting them, you can get a really cool concrete effect.
The sepia tones were done by actually "painting" a full color version, then adjusting the hue and saturation to an orangish tint. You lose all the color, but you keep all the different levels of shading and tone.
All of the blood, scratches and concrete effects are put on their own layer then I adjust the opacity until I get the suitable level of creepiness.
Enjoy.