Narrator

In fiction, a narrator is a voice or character who tells the story. The narrator generally can be divided into several types.

First person: "I walked into the room and I saw a man sitting in a chair." (The narrator is a character in the story, usually the protagonist.)
Second person: "You walk into the room and see a man sitting in a chair." (The narrator is narrating the story to another character through that charcter's point of view. Rarely, the narrator will narrate directly to the reader, as though the reader is a character in the story; this type of narration is almost unheard of outside of interactive fiction.)
Third person, limited: "She walked into the room, nervous, and saw the man sitting in a chair." (The narrator tells the story from the general point of view of one character; the interior mental state of only one character, the woman, may be described.)
Third person, omniscient: "She walked into the room, nervous, and saw the irate man sitting in a chair." (The narrator tells the story from as many points of view as necessary; internal mental states of both the man and the woman can be described.)

An unreliable narrator is a character who tells the story but who does not have all the facts, or does not tell the audience everything he knows. Therefore, the narrator may say one fact is true, yet the reader, who is better informed than the character, knows that a different fact is true. Examples include The Basketball Diaries.

External reference

http://www.netauthor.org/pov.html