On the Willow Garage Blog, you can find out more about the Texas Robot, which is a telepresence robot built out of leftover PR2 parts and off-the-shelf components. One of the interesting aspects of the Texas robot is that it is running the PR2 software components as-is: motor controllers, tele-operation, visualization, etc... The only changes required were modifying the robot model (urdf) and writing new roslaunch files. You can find these changes in the texas package on ROS.org. Any other changes have been improvements that have been useful for both the Texas and PR2 robots, such as updates to the teleoperation controls.