“Shia fighters are said to have used off-the-shelf software programs such as SkyGrabber to capture the footage.”
Why the BBC calls this a hack [cause it sounds cool I guess] I have to idea. This is a classic interception case. Get a program (SkyGrabber in this case) and start receiving the broadcasted satellite communications. The US should not have had insecure satellite communications in the first place.
 Iraq insurgents ‘hack into video feeds from US drones’ – http://news.bbc.co.uk/2/hi/middle_east/8419147.stm