This time, I think it's fair to say that I actually did create a tutorial. I created a series of images from start to finish, with the goal of showing another artist how to take a 2D map and, using a few tools in Photoshop, transforming it into a 3D map.
Here is the final product of my work:
I might come back and do a step-by-step tutorial on here, but for now, here is the link to the photo album I posted on my 365 Create Facebook page. This goes from start to finish, with images and explanations for each step in the process.