Thanks everyone!
Quote Originally Posted by pyrandon
I'd love to hear how you achieved the mountain effects...
The basic relief is exported from Fractal Terrains. In Illustrator I draw in the landcover colors (as general polygons) and export these and the relief into photoshop. Then I change the color of the relief to a nice mix of C/M/Y by converting to tritone (and then back to CMYK of course). Apply a Median filter and a bit of blur, and then set the blending to multiply with the landcover. Oh, and don't forget to blur the landcover to give it a nice gradation from one shade to the next.

-Rob