here’s copypaste from:
There’s also another way, not yet copypasted here: http://www.gimpdome.com/index.php?topic=459.0
1) Start with a blank image of any size
2) Next create your text. Try and use a text that doesn’t have any thin bits on the letters.
3) Next use the perspective tool (shift+P) and drag the edges of the text (into a similar position as below). Then click transform.
4) Next open up the layer tab (ctrl+L) and duplicate the text layer.
5) Make the top text invisible therefore only seeing the original text and background layers. Select the original text layer.
6) Go to filters/map/bump map… and select the following settings:
elevation: 37, depth: 2, the rest: 0
7) Now duplicate that bump mapped layer 4 times
8) Select ‘Text #5’ and with the move tool (M) selected and the text selected press the down arrow key once.
9) Now select ‘Text #4’ and with the move tool (M) selected and the text selected press the down arrow key twice. Do the same on all the bump mapped text layers pressing the arrow key down once more on each of the different texts
10) Now make the background layer invisible. Right click on any of the layers and select ‘merge visible layers…’ In the box select ‘clip to image’ and hit OK.
11) Duplicate your image that you just merged into 1. (should be the middle one in the layers tab)
12) Select one of the copies you just made and with the move tool (M) selected and the text selected press the down arrow key as much as desired (I do it 5 times)
13) OPTIONAL: If you want your text thicker duplicate your text again and with the original thick text selected move it down with the arrow key as much as desired.
15) Finally make the background and original text layer all visible.
16) OPTIONAL: Merge the 3 thick layers together and lower the brightness on it. (Layers/colours /brightness-contrast)
17) OPTIONAL: Merge all layers together so you only have the 1 text layer and the background layer. Right click the text layer and select ‘alpha to selection’, go to scrip-fu/shadow/drop-shadow, I used the following: X and Y = 8, Blur = 8, opacity = 50, make sure to uncheck the ‘allow resizing box’