Before starting with the tutorial itself make sure you have this magnificent free image editor installed and running in your computer. We've placed a “Download” button above these lines for those who don't already have it, just click on it and the InstallIQTM manager guide you through the setup process.

Start by creating a new image (if you've any doubt about that check previous tutorials) make it square, for this example I used 300 x 300 pixels size.

Immediately after that create a new layer by clicking on the new layer button, in the popup dialog just leave the default settings.

Now you can apply color, a pattern or a gradient to the image by using the Bucket Fill Tool, select the filling using the tool's option you'll find in the lower panel of the Toolbox window. To do that you must change the background/foreground color prior the activation of the Bucket Fill Tool and then select either the background or foreground color in the tool's options.

As you can see I applied a solid color to the layer. Next step is to Access the Map to Object dialog by going to “Filters” → “Map” → “Map Object...” in the Image window menu.

In the first tab unfold the Map to menu and select “Box”, check the “Transparent background” check-box, the Light and Material tabs leave them in their default values and go to the Orientation tab and enter the following values: X: 30, Y: 50 and Z: 0,0.
Click the Preview! Button and you should see something like this:

Click “OK” and the rendering process will begin, this may take some time depending on your system's configuration.

And voilà! You've created a cube using Gimp.

Final words
In our next tutorial I'm going to tell you how to apply different colors, patterns or gradients to each face of the cube. Gimp is a really versatile and solid image editor, give it a try! Get your free Gimp installer by clicking on the link below, safety is guaranteed, no viruses, no spyware, no malware of any kind.