iPhone 4 Repair Manual

iFixIt has posted an iPhone 4 repair manual which instructs you on replacing 10 different components including the front panel, rear panel, and battery

Installing-iPhone-4-Battery
Installing-iPhone-4-Home-Button
Installing-iPhone-4-Speaker-Enclosure
Installing-iPhone-4-Dock-Connector
Installing-iPhone-4-Logic-Board
Installing-iPhone-4-Front-Facing-Camera
Installing-iPhone-4-Rear-Camera
Installing-iPhone-4-Front-Panel-Assembly
Installing-iPhone-4-Rear-Panel