Problem Oriented Policing is similar in a way to community policing. It is an approach to policing that emphasizes trying to get at and solve the root causes of crime instead of simply trying to arrest those who commit crimes.
In POP, police try to determine what underlying factors cause crime in a given area. They then try to act in ways that can eradicate those problems. This is, for example, what is going on when the police are active in DARE programs to try to make sure that kids do not start doing drugs. If there are fewer people on drugs, there will be fewer drug-related crimes. This is also the reason for things like police-sponsored athletic leagues. They are meant to prevent kids from hanging around with nothing to do and committing crimes.
POP, then, is an attempt to prevent crimes from occurring by attacking the root causes of crime in an area.