http://www.digitaltutors.com/tutorial/1419-Creating-a-Vintage-Textured-Game-Asset-in-Photoshop-and-Maya 

The overall goal of this project is to learn how to create stylized textures and materials for games. This tutorial will focus on the creation of a vintage sign asset using multiple texturing techniques in Photoshop and ending with a real time version of the sign in game (UDK) with working materials for lights. Using this knowledge, you will be able to create your own assets and understand stylization when it comes to creating textures and establishing identity within game art.