This is an example of hyperbole (exaggeration) that Jesus often used to make a point. In this verse, Jesus is making the point that anyone who follows him must put him above other relationships, including family. Because Jesus often talks elsewhere about the importance of loving people, including one's enemies, he does not literally mean to hate people in this verse.
A similar example is Matthew 5:29-30, which sounds as though Jesus is saying to cut off one's eye or hand if it "causes you to sin." Again, Jesus is using hyperbole to make the point that people should guard against sin. If this were meant literally, most Christians would be walking around with only one eye and one hand.
