Don't do it! I'm one of those guys who fixes everything. I'm really good with my hands. I should have been able to replace my battery. I followed the directions meticulously. Even used a large, mounted magnifying glass at times. Taking the iPhone 3GS apart was no problem. Halfway through the take-apart, I wondered whether all the tiny pieces would fit back together exactly the right way. Too late to stop then, however. I replaced the battery and backtracked to put everything back together. The board didn't want to go back in flat…it just wobbled. It took 2-3 attempts to finally get it in correctly. One of my ribbon connectors was different than the photos (an old model?) and needed to be slipped into place. I really needed the magnifier for that. Got it all together, and the phone would only stay on for a few seconds before shutting down. I went back inside and reconnected that suspicious ribbon connector. Now the phone works, but no camera and the battery won't charge above 50%. Now I need a new phone.