I was a complete newbie as well until I started to build my panel a couple months ago. I am going to show you a technique that does involve cutting wires inside your computer, but trust me, it is a piece of cake. You just have to do it and get over the "I don't want to get into electronics" fear. Once I did that I not only got this to work flawlessly, but I also started to feel confident enough to delve into other things.
The best way I figured out how to do things is this:
First you need to go to Radio Shack or somewhere and buy some quick disconnects and some wire. Actually if you are planning on ordering the NovaGem glowing buttons from GroovyGameGear you can add some male and female disconnects to your order. They look like this:

If you can get insulated male and female ones that's best, but whatever really works. What you do is thread wire into the narrow side and use a wire crimper/stripper . . .

. . . which you can find in any basic tool set like from the Sharper Image or something, to crush the end of the quick disconnect where the wire was inserted so that it can't slip back out.
You are going to cut the red and black wires on one of your CD ROM drive power connectors on the inside of the computer and then strip a little bit of the wire insulation so that you have a nice little bit of wire exposed. You'll then insert the red wire into one quick disconnect and the black wire into another, and then attach the opposite gender quick disconnect to the other end of each. It'll look like this, except with red and black instead of yellow and black:

As you can see I managed to get my coin return lights to power up.
Then you need a terminal block; it looks like this:

That's also on the groovygamegear site. You will take wire from your two quick disconnects and attach each to one side of the terminal. On the other side you'll be able to attach the power cable for your buttons and your ground cable, respectively. It'll look like this:


(you can clearly see the wires in the lower right hand corner of the image, connected through the quick disconnects, to the terminal block)
You'll notice I have red and black on one side and then just two wires on the other. The reason I have all these loops in the block is so that if I need to plug in more than one button, I've got a power source that spreads across the entire one side of the block so I can use any of the terminals on the other side (as long as I match up one with red and one with black) to power buttons.
I know all of this seems complicated but trust me, if you just follow the instructions everything will become crystal clear in no time. Plus as long as you don't have the power to the computer on and you're careful not to touch exposed ends of the wire to the computer when it's on (that's why you should put the quick disconnects on ASAP, to prevent that from happening) you won't even have any risk of killing yourself because you're dealing with 5V DC at a fairly limited amperage so it's not harmful to you anyway. I think Edison ran like 1000v DC through his body when he was conducting his smear campaign against AC power.
Not only that but you will actually have fun doing it -- trust me. Once you're over that fear of delving into the electronics, you'll get all sorts of exciting ideas about what to do with your panel, things you never would've dreamt of before. It's totally worth it.
Good luck and keep us posted on your progress.
Justin