After finishing the lessons in Scott Kelby's "7-Point System for Adobe Photoshop CS3", I had to go back and revisit some of my older stuff.
I started with this JPG image, adjusted the foreground using Camera RAW and then made another image in Camera RAW and adjusted the sky.
I merged the two images in Photoshop and then darkened the sky, lightened the foreground, desaturated the blues and yellows a tad, etc.
It's not remotely realistic. The sky is pretty dark for an image that's looking right at the sun.