20 - 30 minutos
My iPhone 3gs had lost it's juice and my volume botton had broken off. Apple wanted a fortune to repair and no loaners. I use my phone for business and a week without it would be a severe hardship.
The parts arrived timely. The on line diagrams and detailed photos made it easy. The only real problem was me. Small screws and old fingers don't always go together.
I would get a small magnetized screwdriver, a magnifying glass and a make sure you have a black cloth to place screws on. Also make sure you seperate screws by size as you remove them.