A friend of mine had a broken down iPhone 3G. The phone itself was in kind of rough condition. The power button was torn off, the LCD has lines across it and the battery wasn't holding a charge anymore. I figured that before sinking money into a replacement screen, fixing the battery and switch should be done first.
The repair went smoothly following the guides. Just lift up on the contact cables and don't push on them like a nut like I did. It was a great confidence builder and the tutorials were great. Of course, now I know that I have to buy a replacement for the internal power switches as well as a new LCD.
I went out to the local hobby shop and bought a little paint mixing disk. The kind with indentations. I numbered each of the 10 reservoirs and add the screws and bits to them in order. It made it a lot easier to find things. I just need to weigh it down so a hard breeze doesn't send it flying.