well, I would start off with posting this in the right thread(photoshop)
then I would use the pen tool to draw the outer perimiter of the sword(how it sould look)
then I would take a) the gradient tool and fill the sword up
b) take the layer style box, and start messing with it(maybe there's a preset layerstyle in the recources section)
then you can add background and detail,
I know it a very basic version, ut you should start with the basic. And if it has to look really pretty *pretty in the sky*, then you should draw somehting, clean it up(there's a tut about this in the recource sesction) and then use the burn and dodge tools to make selfshadow and highlights!! But this is a way lot more difficult then the basic version

*duh*