To add on to the excitement, Bryan Konietzko released an official promotional poster image which will be given out to fans at the Nickelodeon booth on July 19. He also mentioned "More cool announcements to come!" in his recent tumblr blog post.
Legend of Korra Panel @ Comic Con
Panel: Friday, July 19 : 11:15 AM ― 12:15 PM @ Ballroom 20
*Poster Signing: 12:45 ― 2:15 PM @ Nickelodeon Booth