iFixit

On the back:

• Samsung K9PFG08 flash memory
• Cirrus Logic 338S0589 audio codec (Apple branded). This is the same part as in the iPad.
• AKM8975 - newest magnetic sensor that promises to improve the performance over the prior generation.
• Texas Instruments 343S0499 Touch Screen Controller
• 36MY1EE NOR and mobile DDR

Wi-Fi, Bluetooth, and GPS are all provided by Broadcom and located beneath EMI shields on the front side of the board.

Broadcom BCM4329FKUBG 802.11n with Bluetooth 2.1 + EDR and FM receiver.

Broadcom BCM4750IUB8 single-chip GPS receiver.

Up next we find the second microphone, which is used to cut out ambient noise and improve sound quality when talking on the phone.

You can also see the ambient light sensor and the proximity sensor which are mounted right above the earpiece.

The front-facing VGA camera.

While the 5 megapixel camera on the rear of the iPhone 4 is ideal for video recording, the smaller camera on the front optimizes use of Apple's FaceTime for mobile-to-mobile video calls.

The front panel comes off without too much additional trouble.

The stainless steel body left behind is quite a marvel of gadget engineering.

The front glass panel of the iPhone is reported to be constructed of Corning Gorilla Glass, a chemically strengthened alkali-aluminosilicate thin sheet glass that is reported to be 20 times stiffer and 30 times harder than plastic.

Gorilla Glass holds many advantages as the iPhone 4's front panel, including its high resistance to wear and increased strength from an ion-exchange chemical strengthening process.

LED Backlight for the LCD.

Unfortunately, the LCD panel is very securely glued to the glass and digitizer, with the entire assembly measuring 3.05mm thick. It appears that if you break the glass, you'll have to replace the iPhone 4's glass, digitizer, and LCD as a single assembly.

Surprisingly, the electronic home button switch is attached directly to the home button itself.