An unlocked GSM device can be used with any GSM carrier. They don't seem to care. However that isn't always the case with CDMA devices. Unlocking a CDMA phone, other than an 8830 or 9530 does little for you, if it can even be done. I know for a fact that Verizon and Sprint do not allow any other device on their networks, it has to be their branded device and the ESN must be in their database. I think Bell has the same policy but not sure. Perhaps another Bell user can verify this one way or the other.