The opening show on should take place on December 16th. 2009 and is by invitation only. The official public premiere should now be on what would have been Elvis' 75th birthday; January 8th. 2010. The shows running up to that will be trial shows.
From the Aria resort website:
The king of rock 'n' roll will soon be back in the building in Las Vegas when ARIA presents a once-in-a-lifetime experience.
The creative geniuses at Cirque du Soleil have created a new show exclusively for ARIA. The production pays tribute to Elvis' music and life, fusing dance and acrobatics, live music and iconic tracks, nostalgia and modernity, high technology and raw emotion. In short, the show will be in Elvis' image: powerful, sexy, whimsical and truly unique.