Typically, there are five (5) main positions: two guards, two forwards, and a center. By rule, there is nothing that any one of these positions can do that the others cannot. But they all have traditional "roles" which they usually adhere to. They are listed below.
However, note that many basketball coaches tend to simplify their offense by starting five players who are either wings or posts. Posts play around the basket, and usually get the ball when they're already in a position to score. Wings are ball-handlers with a better outside shooting ability, usually, or at least have the skill to take their defender off the dribble and get to the basket for a closer shot.
* Generally the shortest and fastest players in the team. They are often the best at dribbling and therefore they are often called upon to bring the ball up the court on offense while the rest of the players get into their positions. They are often the leader on the floor, calling out plays, and controlling the tempo of the game. They have the ball in their hands the most out of any position.
* Point Guards are usually the shortest players. They have excellent dribbling and usually play point and on the wings. Should be a good passer and a very good dribbler. Able to use both hands evenly. Cannot be selfish. Sets up the offense.
* They aren't always the smallest- Note, Michael Jordan was a guard and he was 6 feet 6 inches tall and he played the point guard position sometimes
* Point guards are usually the ones that handle the ball. They bring it up and down the court and call the plays. They are essentially the quarterback of basketball.
* There are two distinctly different point guards: those who are score-first, pass-second and those who are pass-first and score-second. Allen Iverson is the score-first point guard, while Steve Nash is the pass-first point guard.
* Examples of a point guard: Allen Iverson, Steve Nash, Chris Paul, Mike Bibby
* Usually taller than the point guard. Often these players are the best shooters from longer distances. They are also expected to be very fast and need to be able to dribble well.
* The back-up ball handler, usually better shooters (hence the name).
* The job of the shooting guard is to get open and find a shot or find another open player to keep the ball moving.
* Usually one of three types of shooting guards: The cutter and slasher, who gets dunks and layups for most of the points; The scorer, who can score in so many ways, often takes tough and contested shots; and the shooter, who love to hit jump shots. Examples of each: Kobe is a scorer, Ronnie Brewer is a slasher, and J.J. Redick is the shooter.
* Example of a shooting guard: Kobe Bryant, Michael Jordan, Tracy McGrady, J.J. Redick
* Vary in mold. Taller than shooting guards but not as big as power forwards, these players are often very versatile, and can either shoot well from long range or get near the basket and get rebounds, etc.
* Forwards are some of smallest players on the team. Usually plays around the wing or corner and usually drives along the baseline. Should be a solid rebounder. A good runner. A hard driver and a good passer.
* Very much like shooting guard, usually starts lower on court.
* Example of a small forward: LeBron James, Carmelo Anthony, Larry Bird
* The next biggest player. They traditionally do not stray out and shoot long shots but play near the painted area and by the basket, trying for short-range shots and layups. Good power forwards are also very good at rebounding. Recently in the NBA many power forwards have emerged and can shoot three pointers very well.
* Forwards fight under the net to get open for an easy lay up. They are post players and are usually taller than the guards.
* Usually larger players (hence the name); starts low with small forward.
* Example of a power forward: Tim Duncan, Kevin Garnett
* Usually the tallest and slowest players on the team. Their primary jobs are to get rebounds and score points when close the basket. They are rarely expected to dribble the ball much nor shoot from more than 15 feet away. Some centers are very dominant at scoring from in close while many others only score a handful of points per game. The best players at blocking shots on defense are often centers.
* The center stays around the paint, which is the colored part of the floor around the basket. Should be a solid rebounder and a good inside shooter.
* The center has to be able to move around and help move the ball and occasionally shoot. For the most part they are very helpful on defense.
* The center is the biggest or strongest player, and is usually interchangeable with power forward.
* Example of a center: Shaquille O'Neal.
* Player positions can also be referred to by numbers: the point guard(pg) is the 1, the shooting guard(sg) is the 2 guard, the small forward(sf) is the 3, the power forward(pf)is the 4 and the center(c) is the 5.
Source: Wiki Answers