I went to see Iron Man 3 with my family recently.
Like all Marvel movies, it has a post-credit scene. In Iron Man 3, this scene is particularly funny.
Unfortunately, my children were acting up - they got extremely bored during the credits. I wasn't able to watch the screen closely during the scene, and I didn't recognize the other actor by face or voice.
Who was the other character Tony was talking to?
My suspicion is that it was
Dr. Bruce Banner
but I may well be wrong.