Yes, it's true. Prior to Bryan Singer's Superman Returns, there was indeed a planned version of the rebooted Superman franchise in which director Tim Burton would remake the man of steel in his quirky style — and Nicolas Cage would portray the hero. The surprising thing is that it got past costuming stage, as is evidenced by this leaked video that recently appeared online.
All reports say that this video is legit, and by the looks of it, comic book movie fans dodged a speeding bullet.