2 - 5 minutes
Dead phone, Apple said they couldn't fix it. Water damage to the dock
Fantastic... easy to follow instructions, tools worked well and I now have a cool see-through back on the phone!
I used a magnifying light to see all the fiddly stuff (like making sure the screws were turning, not cross-threaded, etc.)
Phillips #000 Screwdriver
iPhone 4 (GSM/AT&T) Dock Connector
iPhone 4 (GSM/AT&T) Revelation Kit