I love that the above post referred to the narrator as a "he" because I'm going to suggest that the narrator is actually a woman. But this is one of the beauties of the "unnamed narrator." The ambiguity of his or her identity is part of what makes the story better.
I agree with what was said above, but want to add to it. One of the most deliberate things Faulkner has done through the use of first person point of view is insert the attitude, bias, and general snooty dislike of the townspeole for the Grierson family (and namely, Miss Emily). The entire story is told as a combination of gossip on top of gossip. It is not told chronologically, as if to suggest that the narrator is remembering things in order of her disgust, rather than in the order they happened. And because we don't know the narrator, we're likely to keep listening (out of morbid curiosity if nothing else) get all the gory details, and then side with Miss Emily because we end up despising the voice talking about her.
The point of view in "A Rose for Emily" shapes the story in a unique way. The unnamed narrator is a citizen of Jefferson who is completely familiar with the town and its people, living and dead. Through the narrator, we learn important facts and details about Jefferson--its history and culture--as far back as the Civil War.
The narrator tells the story in his own way, moving back and forth through time, saving the discovery of Homer Barron's body until the very end, creating the story's shocking conclusion. Before arriving at the conclusion, however, he gives readers information that foreshadows the ending. For example, in the beginning of part II, the narrator shares this history:
So she vanquished them [men who had come to collect taxes], horse and foot, just as she had vanquished their fathers thirty years before about the smell. That was two years after her father's death and a short time after her sweetheart--the one we believed would marry her--had deserted her.
The smell, we realize later, is Barron's body decaying in Miss Emily's upper bedroom.
The narrator is a member of the town, but he tells his story in a factual, objective way, without condemnation. Readers are left to draw conclusions and make judgments for themselves in regard to Emily Grierson and the roles others played in her life and death.