One evening, while out with friends, my iPhone had a little too much beer to drink. While I don't mind it imbibing occasionally, it got completely soused this night and ended up shorting its dock connector and top power button.
Following the directions given on the website, the repair was actually quite easy. I took everything apart and got it back together in under 1/2-hour... BOTH times. See below for an explanation.
Like many people, I had issues with the antenna that was installed on the replacement dock connector. After replacement I was getting 1 bar on GSM and "No Service" on 3G.
I searched for a solution and found that people fixed this by just peeling off the old antenna sticker and placed it on the new connector. Instantly went from 1 to 5 bars as soon as the phone was powered back on.
Just save yourself the trouble and do this from the start. I don't know what the difference is; maybe these have been rejected by Apple for that exact reason and that's how they end up as spare parts.