GIMP Plugin Registry

Makes landscapes around these lines, no color tho, that has to be done manually with overlay and multiply layers
Width
Height
Use Thumbnail sizes (400 x 300, good for a quick preview until you get something amazing)
Seed 1
Seed 2
Balance (affects the contrast/brightness balance in one of the mid steps, can give a little more "crisp" to final product) Detail (detail values in the difference clouds)
Depth (gives the mountains some more rugidness)
Blur (smooths out the layer with the lines on it some more)
Lean (how far in the layer is leaned back)
Edge (how far in the bottom edges are moved in)
Interpolate (for perspective plugin) Remove Grid Flatten
Ill try and get a tutorial up somewhere for explaining exactly how it works, and another for getting some color in

note: this can run pretty slow sometimes when working with the larger images (like the 1600 x 1200 wallpapers), hence the implementing of the thumbnail toggle. Also tried only in version 2.4, if any problems just tell me and ill give it a look