I've noticed that authors often show the main character's though process in third person using the prose itself, almost as if the character were the one narrating. Made-up-on-the-spot example:
Albert paced back and forth, looking at his watch every few seconds. They were late. Again. Why did he even bother offering his expertise when they didn't even show the slightest bit of respect? Yes, he was only a journeyman, but when he was a novice he showered his tutors with the adoration a superior deserves! If he had done this with his own tutor, he'd have been rejected immediately. He was going to have to have quite a talking with them. One more situation like this and they were gone, and he would not be persuaded otherwise.
In that paragraph you can clearly see Albert's stream of consciousness, but it's never explicitly stated as such. It's almost like he is the narrator. Heck, when I was little I thought that was the opinion of the narrator. Realizing that it was the thoughts of the character was quite the revelation.
I've also noticed that in first-person stories where the current narrator is very different from his past self, a similar technique will be employed with the narrator speaking the thoughts of his old self.
Is there a name for this technique? Where can I find more information about it and how to properly employ it?