This was done using Gimp 2.2. This assumes you've looked at General Icon Techniques.
- Take the image and clean it up as per your liking. Call it layer p1.
- Put a white border around p1. If necessary, merge down so you have a layer with the border included.
- Duplicate p1 and shrink the new layer (p2) to be 90x90 pixels.
- Duplicate p1 and shrink the new layer (p3) to be 80x80 pixels.
- Move p2 and p3 so that they are in one corner of the image.
- Put in your text where you want it.
- Now here's the interesting bit. Add a layer mask to p2. Select one side of the (inner) white border with the rectangular select. Use a linear gradient fill in the layer mask to make the white border fade away to nothing. The reason why we put the text in first is so that we know where to start the black part of the gradient to make sure that there is no border at all where the text is supposed to go.
- Do the same with the other side of the white border.
- Do the same in layer p3.
- Add other decoration if you want it (I put in a gradient wash).