I used one external source
Thanks to http://www.sxc.hu/photo/828333
Author: halazem

I replaced the sky in the original photo, (with masking) and made a mist effect on the water to create a unworldy kind of look. For this i used gaussian blur and twirl. Added more detail to it with white lines and another blur, twirl. Masked out the rocks for more effect.

The sky comes from Stockxng, a photo from Shannonc5 named incredible sun and sky.

Yesterday i made a robot for the chadelier contest, but found out i couldn't enter yet. I made it solely out of the source picture. I added it to the scene, to make it more interesting.
I primarly used transform, a lot of layers and masking to create the robot. Shadow and highlight detail was made though black and white with several layer blending modes.

Created shadows with free transform, blur and blending modes. after that applied color overlays.

thanks to scanmaster for"Islands near gothenburg 4" image and beeneeb for the "Black Sand Beach in Hana, Maui" image

very simple
a background
some trees
with masking , color blending and layer style
thats the end result

Thanks to cherilyn for the image.

Source only, the universe background was created in PS CS4.