Straight from the heart of SDCC, James Cameron, just announced that on August 21, 15 minutes of his anticipated non air bending movie “Avatar” will be screened for free at cinemas around the world. This will be the same clip that was just shown at the Avatar panel here at the con.

“We wanted people who couldn’t come to Comic-Con to be able to see what you’ve seen so we’re going to take over as many IMAX and 2D cinemas on August 21st,” Cameron explained.

“We’re going to allow international audiences to come and see footage from Avatar for free on August 21st.”

So let it be known that August 21 is officially, unoffically, Avatar day.

A paraplegic ex-marine war veteran is unwillingly sent to establish a human settlement on the distant planet of Pandora, only to find himself battling humankind alongside the planet’s indigenous Na’vi race in this ambitious, digital 3-D sci-fi epic from Academy Award-winning Titanic director James Cameron. The film, which marks Cameron’s first dramatic feature since 1997’s Titanic, will be shot on the proprietary FUSION digital 3-D cameras developed by Cameron in collaboration with Vince Pace, and will offer a groundbreaking mix of live-action dramatic performances and computer-generated effects. Australian actor Sam Worthington stars as the reluctant human settler Jake Sully, with actress Zoe Saldana signing on to portray the local woman who enters into a romantic affair with the hero.

The revolutionary motion-capture system created for the film allows the facial expressions of actors to be captured as a virtual camera system enables them to see what their computer-generated counterparts will be seeing in the film, and Peter Jackson’s Oscar-winning Weta Digital visual effects house has been hired to supervise Avatar’s complex visual effects. Wes Studi, Sigourney Weaver, CCH Pounder, and Michelle Rodriguez round out the cast.

“Avatar” will hit theaters on December 18, 2009.