While trying to disassemble my iPhone 4 to replace the cracked screen, I tugged too hard on the flex cable for the dock connector and tore it. I was stunned looking at the ripped piece! OTL
Having already taken the phone apart (after 3 hours), the repair only took me 30 mins!
Be very gentle with the pieces and place all the screws on a sheet of taped-down white paper. Take notes on the paper to where everything goes! There are very small connections that are hard to notice right away (like for the Home button)