
recently updated!
This Filter only works
on the Alpha Channel of the Layer you're working on.

BackGround

Make a New Layer (the Type Tool in PhotoShop automatically makes
a New Layer for you)
After Typing on the Layer
Uncheck 'Preserve
Transparency' 
like this

Very Versitile - Highlight/Shadow can be at any Angle (by 15
degree incraments)
here I blured the layer slightly to kill the hard edges

Example 2

Make a New Layer

Any Grafix you choose

Original Color is Preserved at any Opacity you choose,
HighLight/Shadow Opacity is Separately Controlled