Porter Novelli is working with Metaio on an augmented reality game for the SXSW 2010 festival this weekend centered on a scavenger hunt model.

The game, called SavangAR, was created for play on an iPhone through the free junaio application and involves clues in the forms of "geotags" left around Austin, the Conference Center, and at events for PN client Rackspace on March 12 March 14.

Here's an explanation by senior VP/social media John Havens and EVP/emerging media and technology Israel Mirsky:

Users can pick up the clues through the camera on their phones within 30 feet of one of the tags.

Players can leave messages and photos at the locations and get points based on how early in the game they find the tags. The game also employs markers created by Metaio that display 3-D images when viewed through an iPhone camera.