Going from this to
Open up your image. Crop and resize it however you like.
Go to Filters -> Enhance -> Sharpen. I set it to 15 and click ok. After that I usually sharpen it once more and sometimes again after that.
Duplicate the layer twice and set both the copies to screen.
Duplicate the top layer and set the copy to hard light. Desaturate this new layer.
Add a new layer and fill it with #d4c2a5. Set this layer to multiply.
Go back and copy the desaturated layer. Drag it to the top of the other layers and set to soft light.
Then I made a new layer and added a border using a brush from teh_indy. You can skip this step if you want though.
That was probably a bit confusing so just to clarify -
Layer #1: Icon base layer mode - normal
Layer #2: Copy of icon base layer mode - screen
Layer #3: 2nd copy of icon base layer mode - screen
Layer #4: Desaturated copy of icon base layer mode - hard light
Layer #5: Filled with #d4c2a5 layer mode - multiply
Layer #6: Desaturated copy of icon base layer mode - soft light
Layer #7: Icon border brush layer mode - normal
Hopefully that wasn't too hard to understand.. it's my first so go easy! Show me what you come up with if you use it :)