Thank you igchy, but from my understanding TwonkyMedia converts (or Transcodes) the video to something that is able to be played on the PS3 & Xbox. Therefore the Laptop would not be required.
Since it is converting the stream as the PS3 or Xbox is playing it, I am concerned about how much processing power this requires. My friend has both an Xbox and a PS3. His daughter has one, he has the other, so there is potential for them both watching something at the same time in different rooms.