According to Moviefone:
[Lyndon] uses a chrome and steel surrogate to pilot around the hallways of his high school. The robot, a 4-foot-tall mobile telepresence system built by Vgo Communications, is equipped with a webcam and microphone that allows Baty to see and hear his classmates and teacher at his home, while a video screen at the head of the wheeled unit allows his classmates to see his own face.Initially built for telecommuters and businesspeople on location, the Vgo robot has a serious advantage over webcams or Skype—it allows freedom of movement, a limitation that webcams haven't overcome. And when your immune system is less than perfect (and more Boy in the Plastic Bubble), you'll take any advantage you can get.
Although most schoolchildren would love an excuse to stay home, Lyndon's social interaction is limited to his parents and doctors. At least Lyndon has the OTHER thing that most schoolchildren want: his own robot. LINK
Take a look at Lyndon and Vgo in action: