HNer, Matt Might, did a quick hack (weekend-type) to control a scribbler robot via BlueTooth via smartphone a while back [1]. Given that ROS (Robot Operating System) is being ported to Android, the capabilities for these systems are going to explode! Soon enough, you'll have phone-based robots that have all the accouterments: 3D perception, localization, etc.

[1] http://www.hizook.com/blog/2011/01/12/ipad-and-iphone-contro...