Even though this is a very small effects, it does contribute much to the 'high-tech' look of signatures, and websites! You can get pixel fonts here for free.
Step 1
Create a new text layer, using a pixel font (obtainable for free). Type a small message, logo, etc.
Step 2
Copy the text layer you made by dragging the layer down to the 'Create New Layer' button at the bottom of your 'Layers' window
Step 3
Change the color of the individual layer to grey (the second text layer).
Step 4
Zoom in VERY close. On the second text layer, drag the grey text down one pixel, and to the right 1 pixel. It should look similar to this
Completed Product
As I said, its a minute effect - although if used efficiently can ad a profound effect to a website or signature, etc! If you have any questions, or comments, please post below so I (or other members) can help answer!