Tweet Phone Unlock Instructions for BlackBerry 7100/7130/7130c:

Note: Remove any SIM that is currently in the phone. After phone
is unlocked, remove the battery, insert SIM as desired and re-
insert the battery. Phone MUST be restarted to use the new SIM
card.
1) Power on
2) Go to Settings
3) Go to Options
4) Go to Advanced Options
5) Go to Sim Card
6) HOLD ALT (Left side Below @) and press: mepp2 (Please note
that you will NOT see what you type on the screen)
7) It will ask you for the unlock code. Enter it and then press
trackball to confirm and your phone is unlocked!