Build a robot with 1:16 RC tank platform and support the tablet with aluminum structure.
Plug-in the RC car servos and ESC (Electronic Speed Controller) to USB servo controller, write a C++ or C# program to control the USB servo controller and maneuver the vehicle.
Integrate the previous USB program with Skype API. Skype API reference can be found here:
Create a C++ or C# user interface to send out the control signals with Skype "Application to application commands" (it's a type of message for Skype to communicate between machines)
Make a Skype call and maneuver the robot from other side of the world!