How To Locate Your iPhone's IMEI Number

There are several ways to locate your iPhone's International Mobile Equipment Identity (IMEI) number.

Where can I find the IMEI number on the iPhone?: The IMEI number can be located by simply typing the following on the dialer keypad: *#06#
Where can I find the IMEI number on the SIM tray of the iPhone 3G, iPhone 3GS, and iPhone 4 (GSM model)?
Where can I find the IMEI number on the iPhone's "About" screen?: From the "Home" screen, select - Settings > General > About - and scroll down. The IMEI number can be located towards the bottom of the screen.
Where can I find the IMEI number on the iPhone's original packaging?: If you still have the iPhone's original packaging you can find the iPhone serial number and IMEI (or MEID) printed on the barcode label.