Aang is a 12 year old boy who is the last survivor of the Air Normads and the current Avatar of the world.
The Avatar is the spirit of the planet incarnated in human form and master of all four elemental bending disciplines (Airbending, Waterbending, Earthbending and Firebending), whose task is to keep balance among the four nations of the world.
The voice of Aang for Avatar: The Last Airbender was Zach Tyler Eisen for 3 seasons which had 61 episodes in total.
However there was an original unaired pilot with some slight differences from the TV series. Some differences were art designs, Katara was named Kaya and Aang was voiced by Mitchel Musso.