Tweet Phone Unlock Instructions for BlackBerry 8700/8700c/8700g:

Note: SIM is REQUIRED to unlock the phone. SIM card can be
inactive, doesn't need to active. 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 and press: mepe (Please note that you will NOT see
what you type on the screen)
6) It will ask you for the unlock code. Enter it and then press jog
dial to confirm and your phone is unlocked!