Every GSM and UMTS mobile phone in the world has a unique 15 digit IMEI (International Mobile Equipment Identity) number. It is a good idea to write yours down somewhere as you will need it if your phone gets stolen.
To find yours follow these simple steps:
Turn on your phone and wait for it to start-up.
Type these keys in sequence, one by one : * # 0 6 #
That's five characters, starting with an asterix and ending in a hash character.
Your IMEI should now be displayed. Write it down and keep the number safe.
This process should work with most cell phones in use.