I always thought there was a distinction between POV and narration. You can have 1st-person POV with either 1st-person narration or 3rd-person narration. So I think the discussions here (http://fictionwriting.about.com/od/glossary/g/firstperson.htm) and here (First person pov with more than one main chars) are conflating two separate issues. Am I confusing terms?
These are tightly connected.
POV (Point of View) tells about the person, "through whose eyes we look". "Perspective" is the name for that style of view. An autobiography will be written from the author's POV, in 1st person perspective - or from POV of some protagonist. A guide will be written in 2nd person, from the reader's POV. 3rd person will be just 3rd person POV - or it may be a book which is technically 1st person, but practically 3rd person, a relation of a witness. In this case you're not stretching the truth saying it's 3rd person from given witness' POV.
Now, for the narrator: this is the person, who tells the reader everything that is not said by the characters. Traditionally, and usually this is the person, whose POV is used, although not always.
For example, in theatre dramas, there is often an explicit narrator, a person who walks onto the scene to deliver a passage, e.g. connecting two acts. This is still a 3rd person experience, as we look at the scene without participating, but it's not us who are the narrators. Another example: there are two narrators, in two nested stories - a story tells about a person who tells a story. That person becomes the narrator, but they could still tell any perspective story, e.g. from some virtual protagonist's POV.
There's also a finer distinction between types of narrators, reaching beyond point of view. You can talk about unreliable narrator, omniscient narrator, partially omniscient narrator, and so on. This tells more about the style of narration than just "who says it, and is it us?"
I strongly disagree with SF's answer.
1) There is fictional 2nd person narrative. It's rare, but it exists. An example is given on the Wikipedia page to 2nd person narrative:
2) There are different theories of narrative perspective or point of view. The most common differentiates between:
3) All narrative perspectives can be told in any grammatical person! This is called the narrative mode.