1) Open your photo with Gimp. Duh!
2) Use the Free Select tool to outline the area you want to keep in focus.
3) File > Copy Visible
6) Click on the eyeball next to your new layer to turn it off (A) then make sure your background layer is highlighted in gray (B). Then go to Filters > Blur > Gaussian Blur. If you can't see your layer box click on CTRL + L and it should pop up.
7) Make sure your Blur Radius is no less than 30. In this tutorial I used 50. The higher the number, the more blur you get. It's really just a personal preference.
8) Once the photo has been blurred, turn on your new layer by clicking on the place where the eyeball should be (A). Your in focus part should now be on top. Go to Image > Flatten Image (B) and you're done!
Super easy huh! The only (small) downfall is that you get a slight halo around your in focus area. As hard as I tried, I couldn't figure out a way to get rid of it.
If you are a bit picky like me and you have some sharp edges between your in focus area and your out of focus area you can use the Blur tool to help:
Just make sure you have "Blur" clicked and your radius is all the way up to 100.
One of these days, I'll make a tutorial on how to select fine, small areas of photos such as hair. That way you won't have the problem above :)
There you have it! You can have bokeh with a point and shoot camera, you just have to do it with your photo editing software :)