Alright so my very good friend Deadly Karma is a master of Gears of War and Photoshop. He recently combined his two passions by posting some of his tutorials on his Clan Website which I would check out if any of you guys are Gears of War Players out there.
The first Tutorial is a basic Technique one for Begginers.
For more advanced users who want to start using Grunge Brushes he made a grunge sig tutorial.
He gets most of his brushes from Deviantart.com
All of his renders are from:
http://www.planetrenders.net/
or
http://render-world.com/
If this helps he'll be mosting more on his site so make sure to check it out.