Suresh C wrote:

Here's my copy of the instructions from my provider.  I assume you have
your unlock code from your provider:

"Before starting the process we have to give you warning. You have 5
tries, for the life of the phone, to enter this code. If you go beyond
the 5 tries your phone will be permanently locked to Cingular network.

If you get code error twice I do suggest you call us before going any
further. From within the US 1-800-331-0500 outside the US call
1-916-843-4685.

1.  For the unlocking of a locked Sony Ericsson, no Simcard is required.

2.  Turn on the handset.  Display will indicate “Insert SIM.

        3.  Press the left Arrow (<) button.

4.  Press the star (*) button twice.

5.  Press the left Arrow (<) button again.

6.  You will briefly see the message “Personalized with MNC2” or
“Personalized with MNC3”.

7.   Wait approximately three seconds.

8.   The display will indicate “Network” and a picture of a closed lock.

9.   Press Select.

10. The display will indicate “Unlock (Net)5” and “NCK:”.

11. Enter the 16 digit NLCK4U code <YOUR UNCOCK CODE HERE> and press okay.

12. The handset will display “Network unlocked” and the display “Insert
SIM” appears.

13. The handset is successfully unlocked.