Ustream
The broadcast provides one of the best ideas yet of what it's like to be an astronaut viewing Earth from the space station.
The footage is not constant - at times the screen appears black or grey either when the space station is looking at the night side of Earth or when the video feed is unavailable - but NASA has uploaded a bunch of previously recorded videos from different times of the day so there's always something to look at the.
Here's the live HD broadcast. It's great when you can catch it rolling over our beautiful blue marble.
Live streaming video by Ustream
NASA said the cameras are housed inside temperature-controlled cases. The goal of the experiment is to see how space radiation affects the equipment and video quality.