There seemed to be some interest on the topic of how to make map borders using GIMP, so I decided to write a mini-tutorial on the Subject. Below I've included a png of what the completed map borders should look like. This is not intended as an exhaustive treatment of the topic, and if anyone would like to add their own tips and tricks to this thread please feel free to do so.
What You Will Need:
In addition to using GIMP 2.6.1, I also make use of a plug-in called Layer Effects
, which is a script that attempts to emulate some of the features of Phostoshop's Layer Styles. I will also be using a Slate pattern, which you can find below. To import this to GIMP, click on the image and save it as a file somewhere where you will know where to find it. Then reopen the image in GIMP and save it as a .pat file in the "Patterns" folder of GIMP (I'm using Windows 7 and in my directory it looks like this: Computer > (C:) > Users > Owner > .gimp-2.6 > Patterns). Close and reopen GIMP, and the Slate pattern should be in your patterns dialogue.
Hope this is useful to some of you out there.