Other case window instructables can be found on Instructables web site.
After looking a this look at at ( Part 2 )
Step 1: Plan your design
Take the measurements of your window and draw whatever you want. Go for a theme or use an image. I just made some freehand drawings of flames.
Step 2: Scan in your drawing (Optional)
using the filters-> Filter-Sketch-Photocopy
You get nice thick lines where the outline is in Photo shop
IF you want text or have your image pointing one way you will need to mirror the image.->Image-Rotate Canvas-Flip Canvas Vertical.
Step 3: Tools
Plexiglas - either from your case or buy some to make a window.
Dremel - or other rotary tool that takes engraving bits.
Flex-shaft - helps a lot to makes the tool feel lighter and avoid mistakes.
Engraving Bits - I used a 107. Any size will work. Smaller if you want detail.
Tape - to hold the template to the Plexiglas.
A good light.
Step 4: Setting up for engraving.
Tape the template to the Plexiglas so it wont move.
I have 3 small windows on my case they are all 9"x7" I am only doing the 2 side windows.