The NBA is the National Basketball Association. The NBA is a men's league only, but there is a WNBA for women.
In this chart from 2013 you can see the average for each position. How much you make really all depends on how good of a player you are and sometimes depends on your age. To get into the NBA you have to be in college for at least 1 year and you have to be 19 to enter the draft.
The NBA has other activities besides the regular season like summer league, the dunk contest, all-star game, 3 point contest, and the skills challenge. There is also the USA team but NBA players to have to play.
