Each mobile phone has a unique identity number called a International Mobile Equipment Identity (or IMEI) that is stored within the handset during manufacture.
An IMEI number is used to identify a handset to the mobile network that it is connected to.
Should your handset get lost or stolen you are usually asked to provide your IMEI number, so that network operators can then prevent the handset from connecting to theirs and other operators networks.
You may also be asked for your IMEI number when buying and downloading software to some phones. This allows the software creator to make sure that the bit of software that you purchased will only be used on one handset and to prevent it from being pirated.
The easiest way is to enter the below sequence into your phone, as if you were dialling a phone number:
*#06#
You will then be presented with your 15 digit IMEI number.

If you have the original box that the phone came in, you will often find the 15-digit number printed on the side. You can also find the IMEI number printed on the inside of the handset, usually where the battery and SIM card are held. You will need to take the phones battery cover off to see this.
