First of you need to take out your jewel preferably without braking it remove the metal shielding then heat the jewel from the back until it gets warm on top (just warm to the touch) then you can use a small screwdriver to lift it and then slide something like a butter knife (for better control) under it and lift it off (be careful not to scratch the case)

Heating can be done with a hair dryer, steam or many other ways just don't use anything that can/will melt the plastic and ALWAYS heat from the backside to avoid discoloration on the top

To get the black adhesive of the back of the jewel just put the jewel in a cool place for a couple of minutes then you'll be able to remove it in one big piece in seconds. If your having trouble try using some try using some Goo Gone and a rag to rub the surface clean.

Here is the easiest way of making your gem clear...

You can either use the oven cleaner or you can grab some MINERAL TURPENTINE.

Simply put a little Mineral Turpentine onto a rag or tissue and rub the green paint off. I was a little careful with it around the chrome text in case the turps hurt the chrome, but mine turned out fine:

Now cut out the plastic under the jewel in any manner you see fit to use leaving a 1/8in lip to glue there jewel back onto. A dremel should do the job nicely.

Now you have a hole in the cover with a 1/8in lip, and a clear jewel; so now we need a light.
Get a 80mm cold cathode computer fan. They are readily available at most decent computer stores and they are all over the web. Also they come in a bunch of different colors.

Unscrew the cathode tube from the fan and glue it to the cover of the xbox.
I used 5 minute Epoxy for speed and strength.

Just get a splitter for the molex connector used for the hard drive and you are good to go. Plug it in, see how it looks.