Well, I almost always say that I'm talking "to" someone, when in reality, I'm talking "with". For me, to talk "with" someone means that you are both equally engaged in conversation; to talk "to" someone implies that you are talking "at" them--that you occupy the higher ground of the conversation. However, as I said, in common speech, you will usally hear the preposition "to".
Depends on the context, but normally it is the same. Perhaps in a way there is a slight perceived emotional difference, talking with someone might imply more of a two way discussion, talking to someone may be more like telling someone something.
That's my view, it probably is the same. if you have a bigger context, I can give you my more definitive view.