How to put a border on your sig..

[Foog]

Here's a better border:

Create two new layers on top of everything else.
Make sure your colors are reset, so hit D.
On the first layer, Ctrl-A.
Right click, select stroke, 1 pixel, black, overlay, 50%.
Go to second layer, Ctrl-A.
Right click, select stroke, 3 pixel, white, overlay, 50%.
Create a new document which is 6 less pixels on height and length than your sig. (I.E. on a 450x125 sig, make a 444x119 new doc. Make sure it's transparent background.)
Select all, right click, stroke, 1 px, black, 50%, overlay.
Still selected all, Ctrl-C to copy. Close document, dont save.
Go back to sig, Ctrl-V to paste. Then you can set your white border layer to overlay or soft light.

VOILA!