Can I just buy another jewel and stick it where the stock one goes?? Just pop out old, put in new? I really dont wanna have to cut open my precious xbox!

yes

Does it just pop out once I get the case open?

you can get it out with stove cleaner or pry it out.... if you pry it out it will break

No you need to heat the underside of the top once you get it off for 10 mins or so, and CAREFULLY ease it off. You may have to keep heating, just dont be too rough. Oh, and if you use a screwdriver to pry it up, protect the case otherwise you'll mark it

its actually kinda all up to what you wanna do, some people will say some are better and some ways really suck. I personally use the heat meathod, a heat gun for about 30 seconds gets it good enough to pry up. just dont use the outside of the case for leverage.
Hmm maby i should do a quick clip of how to do it............

I personally preferred the freezing method if you have enough room in a freezer to stick an xbox top in for a while. I left mine in for about 20 minutes, took it out and thwapped it with the heel of my shoe. Some tuts suggest a hammer, but thats a no-no since you can damage things with something that hard.

i used compressed air can. turn it upside down, pull the trigger and a cold liquid comes out... or a can of freon. freeze that sombitch up reeeeal good.

i do the freezer method. i used to use a heating gun, but i warped a case one time.

the can of air freezing trick works, or the freezer method... i ldid the freezer method and flexed my case top gently... it pryed itself right of, no damaged, never even left any adhesive ont he jewel..it's much easier to get off of the case, just rub it off with your finger, then you can use a hole saw to drill a hole straight through the case and have an opening for light to shine through your new jewel.

Anyone tried using dental floss to get under there after the heating or freezer methods?

Now there's a good idea. I'll try that on the next box I get my hands on.