Forgive me if this has been covered before but I am curious.
I had read somewhere that there is a way to make phone calls via the blackberry data service, hence, free phone calls with out using your minutes. I know that through some internet providers on the net you can make internet phone calls. It seems to me that since the BB uses the internet that this could be possible.
Perhaps you are referring to UMA calling? In which case it is only available on models with wifi and carriers that offer UMA calling such as Tmobile and the 8320, 8820, and 8120 models. Also, it is not free. Unless you have the hotspot plan that provides unlimited mins over uma, mins will be deducted from your voice plan.