I maintain a thread on the Visual Arts section of a writing site where I post "mini" tutorials for backgrounds for sigs and such, but many of them turned out to be longer than expected, so I'm going to post them one by one. Please let me know if you find any errors (I tend to mess up on tutorials) or if I need to clarify something.
Follow this tutorial (zoom in to see it): newbielink:http://www.deviantart.com/deviation/34483364/ [nonactive]
Stop before it says, "Filters > Map > Warp, Layer > Colors > Invert (only if it's a dark image). Select Incadescent as your gradient and go to and Filters > Colors > Map > Gradient Map."
Merge layers and duplicate it. Fill the bottom one with a silvery blue. Set the top layer to Hard Light.