Motorola V551 / V330 / V547 / V555 / V557

I was wondering if anyone knew anything about the "capabilities" of the v551. I read heard something about you being able to unlock the phone. What does it mean to unlock a phone? They also said that you can change the faceplate. Does anyone know anything about any of this? They said you can change the startup/shutdown screens and sounds and change the external display. Please give me some feedback bc i would like to see if there is any truth to this? Have any of you done this? Thanks. Chad