Roodrive is a simple remote control app for a Roomba 500+ robotic vacuum with Bluetooth adapter. What is unique about Roodrive is that the remote control pad floats translucently on top of other apps which allows for first-person view driving of the Roomba. So you can mount one phone on the Roomba and stream video from it with a webcam app. On another phone you can view the live video, and then have Roodrive's control window show up on top of the video. For instance, you can run IP Webcam on the device that's on top of the Roomba and run tinyCam on the other; or run Skype, Google Hangouts, etc. on both.

For more instructions, see: http://www.instructables.com/id/First-person-view-Roomba-driving/