I am currently under a Cingular plan and I already have a phone. If I want to get an iPhone, can I just buy one and use the current plan I have? Or do I have to cancel my old plan and then start a new plan? Thanks in advance.
There is no need to have a new plan.
I also had phone having a circular plan and now I have shifted to iphone and I did not took any new plan the old plan is all that works.