Firstly, open the sig/image you would like the border to be added to:


Then create a new layer (control + shift + alt + N), and select the POLYGONAL LASSO TOOL:


Hold Shift and use the polygonal Lasso tool to outline where you want your border to be, and create various effects.
Once you have created your border, click SELECT>>INVERSE, then press control + back space., and press control + I to choose either black or white (can be changed to any colour later)


Now you can edit the colouring (control + U) and add effects (right click>>Blending options)

You may also use the Polygonal Lasso Tool to create additional patterns.




NOTE: This can create absolutely any style of border, the border I created was extremely simple and completed in 30 seconds.

to add to your tutorial, you should probably fool around with the Bevel and Emboss to give the border depth. Also, mess with the shadows. All under "Layer Style"