At the moment, NASA streams video from one of a number of cameras mounted outside the ISS:
http://www.nasa.gov/multimedia/nasatv/iss_ustream.html
You can also follow ISS ground-track in real time (scroll down to zoom out):
http://iss.astroviewer.net/
In November, a Soyuz launch will deliver 2 much higher quality/resolution cameras to be mounted externally after an EVA:
http://www.urthecast.com/
This is a private company venture & should provide some pretty cool
on-orbit imaging!
Dean