This technique gives text an interesting cartoonish 3-D appearance.I think it resembles something that you might find in a comic book. Startby opening a new file, 400 x 150 pixels, 16 million colors with a whitebackground. Now lay down some text. Make sure that you have Floating selected.  I think this effect looks best with a font that has a lot of angles. HereI've used a font called Klingon Blade, 72 pt bold.
 
 

Now go to the Selections menu:Invert. The area outside of your textshould now be highlighted. In the Image menu choose Effects: Chisel. CheckTransparent, and set the size to 12. Your text should become nicely 3D.Invert your selection again so that your text is selected.

This is just a bit dark, so we're going to lighten it a little.In the Colors menu, select Adjust:Hue/Saturation/Lightness. Set the Hueand the Saturation to 0, and the Lightness to 50.

Okay, here's where we start to get that cartoonish appearance. Inthe Image menu, go to Edge: Enhance More. This will give a bunch of linesand interesting details.

To complete the full effect and bring out more detail, choose Colors,Adjust:Brightness/Contrast.  Set the brightness to 0 and the Contrast to100

Personally, I like the white highlights.  But if you thinkthat they make your graphic look messy, set your background color to whiteand use the replacer brush to fill in the highlights with your text color.I would recommend setting the brush size to a large value, such as 100,and the Tolerance to about 10.

As a variation, set your foreground to a color that contrasts withyour text before you use the Replacer brush.

To finish, set your background color to white, and then go to theColor menu and select Set Pallette Transparency.  Set the PalletteTransparency to the Current Backgrond Color, and then save your file asa GIF.