As per a Cav tweet today - this evening on Sky Sports News there is a half hour documentary titled "Special Report - King of Sprint" about Cav. (Streaming usually available - currently on stream 3)
The blurb on the Sky TV planner describes it as follows:
"Unprecedented access to Olympic cyclist Mark Cavendish. He talks about London 2012, Team Sky's hopes for the new year and why he thinks cycling is the cleanest sport around".
Starts 7.30 UK, 8.30 CET, 2.30 US Eastern, 6.30 am Melbourne