Sup!
I was stalking around on CGTextures a bit and came across a free-to-download Photoshop script that seems really nice.
If you visit the page it gives you a quick overview of what it does with examples and whatnot.
Basically, it takes images (best use PNGs with transparency) as input and randomizes and scatters them either across the entire canvas or even a masked layer to create patterns that are not obviously repeating.
Just wanted to throw that out there, might help a couple of people with their texture maps. :)
Cheers