AICN says:
Armie Hammer will play the Lone Ranger, partnering with Johnny Depp's Tonto under Gore Verbinski's direction. He seems a little young to me, but I think he was terrific in The Social Network so I think they cast well. Once Depp finishes up his Tim Burton Dark ShadowsARK adaptation, filming will start on this Western blockbuster, to be released in fall, 2012 (possibly).