The Last Airbender: Legend of Korra

Set at least 70 years after the defeat of Phoenix King Ozai and Princess Azula in the series finale of the original show.

In order to avoid repetition of Aang's adventures, the creators wanted to root the show in one place, called United Republic, a steam-punk style metropolis where people of all nations, benders and non-benders, live together, founded by Aang and Zuko and built after the 100 year war. The city's police are metalbenders led by Toph's daughter and taught by Toph herself. A group of anti-benders, called the Equalists, use Ty Lee's chi blocking skills.

In the show, Korra will have to learn Airbending from master Tenzin, son and youngest child of Avatar Aang and Katara, and contend with an anti-bender revolution taking place in United Republic.

San Diego Comic-Con Trailer:

It's almost 2012. After watching this trailer, I'm more excited than ever. The 2011 San Diego Comic-Con revealed more stuff.

Tenzin will be voiced by J.K. Simmons. Kinda makes you think of Tenzin wanting pictures of Spider-Man.

Dante Basco will be lending his voice in this series again. According to his Twitter account, he will be voicing a new character which is somehow related to Zuko.

Korra's friends shown above is named Mako and Bolin. Mako and Bolin are brothers but bend different elements. Mako is a fire bender while Bolin will be a earth bender. Mako is named after Mako Iwamatsu who actually voiced Iroh for the first two seasons of Avatar.

Source: 
http://www.legendofkorrafans.com/