This is a very simple effect with a nice result; a great beginner tutorial! I'm using GIMP 2.4 for the screenshots, but this can easily be done in GIMP 2.2. However, the menu layouts may be different. If you run into any snags, let me know.
Click on the download link to the left and download the pdf to view at your leisure. If you would rather view the tutorial online, you may do so here: www.gimpdome.com/forum/index.p…
Enjoy! Let me know if you have any questions or need clarification.