In this tutorial I will show you have I make most of my signature boarders, it is actually quite simple and takes very little time.
Step 1: Make 3 new layers on the signature you would like to make the boarder on
Step 2: Set all the layers style to Soft Light
Step 3 Select All by going to the toolbar and click Select -> All (Don't worry about flattening your image)
Step 4 Select your bottom layer by clicking on it in the layers palette and go to Edit -> Stroke (On the Toolbar)
A box should appear like this...
Width: 3
Color: Black
Step 5: Select your middle layer and go to Edit -> Stroke again but this time edit the following:
Width: 2
Color: White
Step 6: Select your top layer and go to Edit -> Stroke for a 3rd time but this time edit the following:
Width: 1
Color: Black
Now you should have a color clear boarder unique for almost any signature.